In a book that Business Insider noted as one of the "14 Books that inspired Elon Musk," J.E. Gordon strips engineering of its confusing technical terms, communicating its founding principles in accessible, witty prose.
For anyone who has ever wondered why suspension bridges don't collapse under eight lanes of traffic, how dams hold back--or give way under--thousands of gallons of water, or what principles guide the design of a skyscraper, a bias-cut dress, or a kangaroo, this book will ease your anxiety and answer your questions.
Or Why Things Don't Fall Down is an informal explanation of the basic forces that hold together the ordinary and essential things of this world--from buildings and bodies to flying aircraft and eggshells. In a style that combines wit, a masterful command of his subject, and an encyclopedic range of reference, Gordon includes such chapters as "How to Design a Worm" and "The Advantage of Being a Beam," offering humorous insights in human and natural creation.
Architects and engineers will appreciate the clear and cogent explanations of the concepts of stress, shear, torsion, fracture, and compression. If you're building a house, a sailboat, or a catapult, here is a handy tool for understanding the mechanics of joinery, floors, ceilings, hulls, masts--or flying buttresses.
Without jargon or oversimplification, Structures opens up the marvels of technology to anyone interested in the foundations of our everyday lives.
James Edward Gordon (UK, 1913–1998) was one of the founders of materials science and biomechanics, and a well-known author of three books on structures and materials, which have been translated in many languages and are still widely used in schools and universities.
What an incredible book! The best layman's introduction to a scientific topic that I've read since Feynman's QED. The author is also hilariously British and doesn't waste an opportunity to rag on the French.
Much of what I write below is copied verbatim from the text, but am too lazy to identify what with appropriate quotes.
These notes constitute about the first 175 pages, I should get around to documenting what I learned in the back half at some point.
basic definitions - Streess = s= load / area = MegaNewtons / meter^2 - Stress measures how hard atoms in a material are being pulled apart or pushed together - Strain = e = increase of length / original length - Strain is how far atams are being pushed or pulled - Strength is the stress needed to break a material - Young's modulous of elasticity ('E') = stress/strain - Young's modulus aka stiffness - Hooke's law says that all solids change their shape - by stretching or contracting - when a mechanical force is applied to it, and it is this change of shape that allows an object to push back - Strength is not the same thing as stiffness (e.g. a biscuit is stiff but weak, steel is stiff ad strong, nylon is flexible (not stiff / low E) and strong, raspbery jelly is flexible (not stiff / low E) and weak - resiliance is the ability to store train energy and deflect elastically under a load without breaking/causing permanent damage - ductile materials are those that, when pulled in tension, have stress-strain curves that depart from Hooke's law, after which the material deforms plastically (think chewing gum - Critical Griffith crack length is the point when a crack goes from being safe and stable to being self-propagating and very dangerous. = 2WE/(pi*s^2) where W=work of fracture in J/m^2, E = Young's modulous in Newtons/m^2, s = average tensile strength in the material near the crack in Newtons/m^2. - work of fracture (aka toughness) is the quantity of energy requried to break a given cross-section of a material - emulsions are drops of one liquid floating within antoehr liquid - elastomers are materials who can extend to great strain, sometimes 800% (e.g., rubber) - Poisson's ratio says that every material has a constant ratio of strain in one direction when a stress is applied creating strain in a perpindicular direction. q=e2/e1 where e1 = strain in the direction of s1 and
cracks - material has stress "trajectories" running through it, which get concentrated (jammed up) at cracks or divots - If a material has a stress s on it and develops a crack/notch with length/depth L and radius of r, then the stress at the tip is no longer s but instead is s(1+2sqrt(L/r)), which means a round hole will have stress of 3s but a corner, which has a low r and a large L can be much higher. This is why ships often break in two starting at corners in doors - Cracks are even worse, because the radius of a crack is tiny making stress at the tip of the crack much higher than the stress elsewhere - Sometimes you can concentrate stress by adding material, making a sudden local increase in stiffness (think new patch in old garment or thick plate of armor on the thin side of a warship). Stress trajectories here are diverted justas muchby an area which strains too little as it is by an are which strains too much, like a hole
energy - one Joule is roughly the energy with which an apple would hit the floor if it fell from a table
anchient warfare - A palintonton or ballista is much more effective than a trebuchet in doing work. trebuchets could only store about 30K joules of potential energy, while ballistas were ~10X that - bows are dangerous to release without an arrow because there is nowhere for that energy to go but back into the bow
nature - spiders webs have two different kinds of threads. long radial ones that carry the load of the structure and are 3X more stiff than the circumfrential threads, which do the work of catching bugs. These more resiliant threads are known as tension members
fracture energy - Work of fracture is not the same as tensile strength, which is the stress (not the energy) needed to break a solid - most structural solids (glass,pottery, cement,brick,stone) which we use in technology only require 1 Joule per square metre to break all the chemical bonds on any plane or cross section. these are known as brittle solids. - we do not use brittle solids in applications where they are in tension for this reason. They don't have low tensile strengths (i.e. they need a low force to break them) but because they need only a low energy to break them. - tough materials can have the same strength as a brittle material, but they are able to deflect stress much deeper into their material, increasing dramatically the work required to fracture the material. in other words, with tough materials, molecules living deep within the material absorb some of the sstress - The energy needed to grow a crack comes from the release of strain energy in material that is separated by the crack. The release of strain energy tends to be over an area that is two triangles with one side the depth of the crack and the other side the exposed surface of the material. The area of released strain is the square of the depth of the crack, which means if a crack is length L then the strain energy release grows as L^2. Therefore, as a crack length grows from 0, the beginning of its life requires net consumption of energy (more energy put into it than released), but after a while the crack reaches a length where it net releases more energy than it absorbs. This length is called "critical Griffith crack length". - The local stress at a crack's tip can be very high - much higher than the official tensile strength of the material. The structure will still be safe and not break so long as no crack or other opening is longer than the critical Griffith length. - The length of a safe crack depends upon the ratio of the value of the work of fracture to that of the strain energy stored in th material, or inversely proportional to its resilience. - Rubber will store a lot of strain energy but its work of fracture is low so the critical crack length is very short, which explains why baloons pop the way they do, in a brittle matter. - One way to be resilient and tough is to be like cloth or backet work and wooden ships and horse-drawn vehicles. In these things the joints are more or less loose and flexibile and so energy is absorbed in friction - In a really large structure like a ship or a bridge, we want to be able to put up with a crack at least 1-2 meters long with safety. - the failure of a structure may be controlled, not by the strength, but by the brittleness of the material - the toughness of most metals is reduced as the tensile strength increases. You can cheaply double the strength of mild steel by increasing the carbon content, but you would reduce the work of fracture by a factor of ~15. So if you double the working stress of a streucture this way, the critical crack length will be reduced by a factor of 15x2^2=60 (x2^2 is the two triangles on each side fo the crack). This means if the safe crack was originally 1 meter long, it will now measure 1.5cm - But if you have a small object (like a bolt) you are ok with crack lengths that are very small, so we can use high strength metals and high working stresses more safely in small structures than in large ones. The larger the structure the lower the stress wch may have to be accepted in the interests of safety.
pressure vessels - the pressure inside a spherical vessel is rp/2t where r= the radius of the vessel, p = pressure, and 2 = the shell wall thickness - for a cylinder, the stress along the shell (i.e., longitudinally) is the same as that in a spherical vessel rp/2t - teh circumferential stress in the shell of a cylinder is rp/t, meaning it is 2x the longitudinal stress, which explains why sausage skins split longitudinally when they are cooked because the skin can't handle the circumfrential stress - this has effect in sailing, where chinese junk sails are rigged so that as wind pressure increasesthe radius of curvature diminishes and the tension force in the canvas remains roughly constant no matter how hard the winds may blow - the only sort of elasticity which is stable under fluid pressures at high strains follow an exponential stress~strain curve (our veins and arteries operat under ~50% strain, and wouldn't work if they were under rubber-like straess-strain curves). This curve means you don't need much stress at first for any strain, but after a while the slope increases dramatically - the heart works in that during the pumping (systolic) part of the cardiac cycle, much of the excess of high -pressure blood is accomodated by the elastic expansion of the aorta and of the larger arteries; this has the effect of smoothing the fluctuations of our blood pressure. - the elasticity of the arteries therefore does the same job as the air-bottle affair which enegineers often attach to mechanical reciprocating pumps - this is why, if artery walls stiff and harden with age, the blood-pressure is likely to rise
joints & fastenings - a lapped joint creates stress concentrations at the two ends of the joint, which is why the strength of such joints depends mostly on their width and not the length of overlap between the two parts. This makes simple rivets very effective - for rods screwed into an anchorage, nearly all of the laod is taken out by the first 2 or 3 threads near the surface, making any extra length of rod within the socket ineffective - this is true when two components of the joint have simialr Young's moduli or when the rod/tension bar is less still than the material of its socket/anchorage. But if the rod or bar is substantially stiffer than the material into which one is trying to anchor it, the stress situation is often reversed and the concentration may exist mainly ata the bottom or inner end of the rod. - riveted joints are heavier than welded joints, but they are also easier to inspect, and often act as crack-stoppers. Most importantly, riveted joints can slip a little and so redistribute the load - rivet holes normally are punched then reamed. The reaming at the end makes the hole stronger and with fewer cracks that were made during the punch - in theory a welded joint should be watertight, but seldom is. In practice, rivets are cheaply caulked, but that can't be donee with a welded joint, so instead a liquid sealing compound is injected under pressure into the weld.
surface tension - tension in a liquid surface differs from Hookean tension in three aspects: 1. the tension force does not depend on the strain/extension but is constant however far the surface is stretched, 2. unlike a solid, the usrface of a liquid can be extended without breaking, 3. the tension force does not depend on the cross-sectional area but only upon the width of teh surface. The surface tension is just the same in a deep or "thick" liquid as it is in a shallow or "thin" one. - so if two droplets join up to make one droplet of twice the volume, there is a net reduction in the surface area of the liquid and therefore the surface energy. So there is an energy incentive for drops in an emulsion to coalesce and for the system to segregate into to continuous liquids. - if you want the droplets to remain separate and not coalesce, then you have to "stabilize the emulsion" so they repel each other. This can be done with electricity, which is why emulsions are affected by electrolytes like acids and alkalis
The author's purpose is to introduce the basic principles of structural engineering in a way that leaves the reader with good intuitions about how structures work, an appreciation for how the field has evolved (and, in turn, how we've evolved with it), and optimism for what the future holds.
On the basis of fulfilling its purpose, the author does a great job. The author breaks down difficult concepts into understandable chunks. He uses math judiciously to make principles more relatable. By the end of the book, you can walk around a construction site and have a much better understanding of what's going on. More so, you're going to have a humility for all that you don't know.
One of my biggest takeaways, personally, was how little we understand of why structures work and how much of our recent experience with airplanes and bridges has been only after structures failed catastrophically.
I detested the author's tone. To the author's credit, he wrote in what certainly seemed to be a sincere tone, so I suppose that I may just detest him. He writes in the manner of a charming, elderly British professor.
What makes that more grating than charming to me are: - His obfuscation at times by relying on obscure historic or British references - His prejudices, including rhetorical asides that repeatedly suggest that little boys become engineers and little girls become frivolous targets for little boys to woo and that those who question whether British imperialism had downsides should be summarily dismissed
With no real relevant educational or vocational background, I came to this book for the title and inspired chapter headings ("Strain energy and modern fracture mechanics--with a digression on bows, catapults, and kangaroos") and stayed for the captivating asides: "All over the world bridge-building used to be associated with children’s dances...and with human sacrifices which are not just legends. At least one child’s skeleton has been discovered immured in the foundations of a bridge."
Along the way, Gordon's casual and accessible manner of discussing how structures work--which happens to apply to pretty much everything, including the human body and its tiniest parts, e.g. blood vessels (an observation that, to me at least, wasn't already so obvious)--made for unexpectedly compelling and effective reading on a variety of topics that may sound somewhat specialized to those of us without engineering backgrounds. (I never thought I'd think so much about torsional stiffness, for example, or find my life marginally improved by knowing more about it.) But Gordon's prose has a way of making you step away from the book and into your environment with fresh eyes, newly aware that things may or may not fall down all because of a few fundamental facts about tension and compression, stress and strain. It's a preoccupying worldview; I can see why people end up structural engineers.
Recommended to anyone who is a structure or interacts with structures (one doesn't necessarily have to live a structured life), and is above say grade 6--there is some math here and there. Mileage may vary for those prone to anxiety; as it turns out, yes, your house *might* collapse without warning, but at least you'll know, should you be out when it happens, that it was almost certainly because the attic floor gave out and not that the roof caved in.
Consistently illuminating - I read this book with the intention of seeing how learning about physical/engineering structures would translate/resonate for Organisational Development.
And it does. Gordon doesn't see a 'clear distinction between material and structure', for example - which I think is a really interesting insight.
It's fun, there's lots of interestingly powerful new words to learn, and, although it's very engineer-ish, I managed to grok most of it.
Structures is, in terms of classes at the University of Florida, Mechanics of Materials and its lab, as well as Mechanical Design 1 and 2. Anything that is covered in these classes is covered here with a bit less math. Yet, while the textbooks for these classes may be dry and direct, Gordon is willing to make jokes, go on tangents, and explore his opinions. This makes an engineering book- beyond all expectations- a page turner.
More than one of my professors at UF used to be a consultant. When things blew up or went wrong, it was there job to go to court and point fingers after having studied the shit out of whatever blew up. And these stories were always the best stories. Tension? Compression? Fatigue failure? The best examples are non-examples. "Look on this wreckage, ye mighty, and despair-- please don't do this or our college gets a bad rap." Structures has tons of these examples, and as the book goes from the basic principles of factors of safety and critical crack lengths up to arches, we get more and more of them.
The last few chapters are calls to action: Failures in structures are almost always due to lazy designers or lazy manufacturing and these are critical moral failures of Biblical proportions. Parallel to this is failures in aesthetics: an engineer is mostly likely designing something that many people will use. Therefore, it is absolutely critical that what they're designing /is nice/. The Spartan ethic of functionalism is too narrow and close-minded.
Structures is a good book for the young engineer or the layman. It gives a -forgive me- structure to one's thoughts about structures. Because it deals with not just buildings, but vehicles, tools, and living things --like us-- it is important for the construction worker, the mechanic and the doctor.
This book was so interesting, really really interesting, but... always is a "but" in the unfinished books shelf isn't?, well the beginning was amazing and it maintained the pace -at least to 36% when i drop it- but the thing that bug me was the parallelism that the autor made of how the structures work with the human anatomy. I have instruction in basic mechanics -I am an engineer- and i love all that stuff of stress and strain in structures and objects, but when you start saying that a lot of strain on veins tissue can provoke an Aneurism... well, or excess of vibrations can provoke that your veins go zig zag on your body, and you say that tendons can be cut with a little knife but can sustain greats weight loads, all of this makes you start thinking about thinks that you should not think about. Of course all of this things are true, at least the behavior of this structures knowing their composition is predictable to some degree, the book is honest, but mixing what i know of engineering with tissues and the heart, and the tendons, and the arteries, well i don't want to lose my mind, no thank you.
Хорошая разминка для мозгов. Инженерия это все-таки отчасти наука, отчасти искусство. Поэтому книга получилась с поэзией. Читал из списка Илона Маска, поэтому настроен был с большим интересом, чем если бы сам нашел. Это помогло дочитать книгу, хоть и после нескольких месяцев медленного прогресса. По результату - обещание книги выполняется, намного лучше понимаю как обеспечивается прочность конструкций. Здания, мосты, корабли, самолеты - нашлось место всему
You rarely see such a holistic cultural knowledge in a "STEM" professional. Quoting profusely from ancient Greek plays, historical industrial-age documents, etc. In general, this makes for a delightful read.
The actual engineering is explained very well, and often one feels a powerful sense of expansion in intuition, which is a feeling any good book explaining mechanics ought to do.
The last chapter on aesthetics is a surprising testament against functionalism, efficiency and other distinctly modern forms of hubris. He has no qualms in admitting that almost all modern constructed structures are ugly and demeaning to the spirit.
Since man can't help but to leave an imprint of himself in everything he does and creates, through the hideous architecture of today we see a mirror into the "mean little souls" of those who govern us. He decries the attempt to limit all design considerations to functional aspects:
"Too often nowadays our subjective judgement clashes with our scientific (or banausic) judgement. But we sweep the aesthetic judgement under the carpet at our peril".
He also defends formalism, the use of rules and structure in the creation of buildings, poetry, art, etc. By following a stylistic tradition, we have parameters on which to compare ourselves. The idea that by abandoning rules we liberate art is hubristic. He asks himself if Jane Austen would have been better if she "had felt free to make use of bad language and overt sex".
In closing, here's a last quote I found interesting:
"Modern art and architecture make a great parade about their freedom from traditional forms and conventions - which is possibly why they have achieved so little".
This is Engineering 101. or a primer for it. It was written in as understandable a manner as possible for the subject matter, that is to say that while I may be an engineer I am not an engineer of this type so I had to take a step back think about what the author was saying...think about it some more and then go ahh or F' it, I dont really need to understand that to get the gist of this book. I did bits of both. This being said this was a very interesting book. I enjoyed it more than I thought I would and that is saying a lot about a book thats subject is basically math.
I read this because one of my children is studying to be a real deal engineer and I wanted to at least be able to understand some of the things they are excited about and this book accomplished that mission. Would I recommend it? Yeah probably for my geekier friends but not for for the artsy or history/literature inclined types. I will repeat you will learn the very basics of engineering in this book and if this appeals to you give it a go just go in knowing it is starting to show its age just a bit but the basics are still the same.
Very interesting book, I learned a lot. Gordon's prose is readable. He is also opinionated and throws in just the right number of anecdotes. I read this book while also watching the "Great Courses" class, "Understanding the World's Greatest Structures," by Stephen Ressler, and think those lectures covered a lot of the same material but with more compelling examples, buildings and bridges.
"It is energetically advantageous for a weight to fall to the ground, for strain energy to be released -and so on. Sooner or later the weight will fall to the ground and the strain energy will be released; but it is the business of a structure to delay such events for a season, for a lifetime or for thousands of years. All structures will be broken or destroyed in the end -just as all people will die in the end. It is the purpose of medicine and engineering to postpone these occurrences for a decent interval."
It's a nice read if you're interested in getting a basic grasp on mechanics. With a background in mechanical engineering, I did enjoy the historical anecdotes and the occasional practical note. However, the author spends so much time elaborating on basic concepts like tension, stress and strain that I'm not sure that I'd recommend it to anyone who has followed at least a basic course in mechanics. His switching between serious explanations and silly jokes doesn't feel well-balanced either - I, for one, am not interested in the Poisson's ratio of the author's tummy.
Moreover, for a book about structures, this book is structured very poorly. There's no conclusion and each section of every chapter is a completely different subject without clear coherence or story.
If you have zero prior knowledge of mechanics, his detailed explanations, mixed with humour and history, might be just the right accessible starting point. To anyone else, I would not recommend it.
Writing a book on engineering has two dangers. If one uses too much detail, formulas and numbers he will scare the reader with complexity and probably also bore him to death. If however the writer uses too little detail or does not venture into important technical concepts at all, it will appear as if he has no insight in the matters himself and tries to "wing it". Mr. Gordon manages to avoid both pitfalls and deliver an entertaining book full of examples of buildings, bridges, boats and aeroplanes and the structural concepts that underly them. It really does feel like I'm one step closer to becoming Elon Musk after reading this (even though it was written in the seventies!)
Full of practical information and fascinating insights. For instance, the human body has very little skeleton and a huge number of sinews. Compression structures never fail by compressive failure: they buckle or topple, and this is surprisingly expensive to avoid.
However, Gordon is rather too preachy about the ugliness of modern architecture, which is why I haven't given him five stars. Also, his previous book, "The New Science of Strong Materials" is better focused.
Even if the topic of the book is quite interesting, its contents are, ironically, poorly structured. It reads like the ramblings of a retired engineer listing things he recalls about his job, without following any particular order. The writing is a bit confusing as well, but I guess that has more to do with the writting style of the 1970s.
Nicely explained stress/strain/torsion relationships to strengths of materials for architectural needs... whether human infrastructure or biological systems. Irreverent and focused on accidents and what for most of human history has been pragmatic guesses and extrapolations rather than maths, I enjoyed it.
About as good a book on the subject as one could hope for - far more eloquent than engineering textbooks. Goes through the theories of stress, strain, fracture, and more steps in the process of structural engineering, in a way that’s relatively easy to follow.
Gordon's old classic is very digestible with only the bare minimum for equations to cover all the concepts and is able to ingrate and contrast biological structures with man made materials for a source of biomimicry before it came to a larger conscious recognition and name (naming something usually give some power of it to dredge it from the subconscious hidden depths). So in that spirit of connecting similar patterns, I think this makes for a good abstract structure of social engineering:
*Social Engineering Metaphor to Materials Science - Most of the time sociologists with use network analysis for social groups as in Nicholas Christakis's "Blue Print" or Lydia Denworth's "Friendship." the method entails measuring links (or relationships) and nodes (people) and the named direction of friendship (if you name someone but they don't name you the arrow could point one way, the other if reversed, and both ways if for both).... there are measures like transitivity (how many of your friends are friends with your friends) and other other phenomena such as the '6 degrees of separation from Kevin Bacon' in Steven Strogatz's overview of network theory in "Sync." There goal is to try and illuminate how these networks are packaged, how they break, what's unique about nodes/links, and the end goal of trying to strengthen the structure as a whole and improve its function and resilience (anti fragility would take too long).
- Bonds - In Rodrigo Quian Quiroga's "Neuroscience Fiction" there is an often reported case of visualizing Jennifer Anniston (they used celebrities) and mapping neurons to see how the system works... Information in the brain is stored in what looks like a network map with a "key" if you're familiar with database programs. So there is a unique neuron that tries into trees of neurons in the visual cortex for images of the actress, tied to ones with 'Friends' (pun), her other movies if you've seen them, as well as auditory neural patterns that correspond with her name or or voice (way more complex but that's the gist from evidence I've seen so far). Now these can be flavored with different neurotransmitters with likeness or similarity as in Robert Cialdini "Influence" which would make sense since aspects of that person's neural trees could be similar and thus understood and resonate with your own (having common interests like you tubers, politics, hobbies, etc). It could be flavored with oxytocin as in love (Dr. Huberman had a video with love as a mapping function as well with loved ones been wired in close with an expectation of how long it would take to see them and the pain of losing them and not being able to find them). But there are also negative painful flavors that would keep them in the network but not the traditional one as they would be adversarial links or repulsive bonds or fractures in this case. So similar to chemistry one could make much broader and more diverseness links with not only other people but symbolic cues as well pertaining to social structures.
-Shells - In chemistry there are shells that enclose the nucleus or node in this case and get larger and more complex as one moves from the inner circle... It seems fitting that the S orbital has two spots that one could assign to the parents who usually give the greatest influences on the person's later social development... from there it's not as simple as there are possible siblings, and other family members moving out but that could be one repeating shell. Friends of different intimacy and setting in another though transitivity could draw them all together. Shells, for work, education, entertainment, exercise, region, politics, etc with different strengths and capping out around Dunbar's 150 bonds for known people at least though weaker bonds exist (especially in information flows). But it should also be noted that the metaphor doesn't hold exactly as the bond for various institutions of their own as shell connections that can scale into larger super organism/structures like companies, movements, nations, etc with organizational structures as well.
*Stresses - With that loose framework we can apply it to why these structures collapse or their parts fail and the word stress applies to both materials and people often tend to break both with enough of it.
-Compression - This is stress in the external force pushing inward. As a gender general overlap this would be more masculine stress... a threat from without... a lion, tiger, or bear... or another tribe or the possibility of starvation (materials have both properties but in different amounts). Hardness is a measure of a material's ability to take stress when pushing together at both ends... in institutions this is often complimented by working "hard" or being able to bear a lot of external responsibility without "cracking under pressure" and "letting down" the load. Gordon has several tables listed and I'm sure there would be a way to measure and change individuals for given tasks (military personal, law enforcement, medical professions, etc) but all materials have their limits. It depends on how the material or institution is structured which also plays a huge role in distributing this stress across its members of various characteristics.
-Tension - Stress in this form is pulling apart at both ends of a material. More so for example, this seems to be a more feminine stress (in terms of dealing with it). Psychological warfare usually targets this area (and would be much more effective with consumerism) instead of a threat from there is the threat from within... paranoia, suspicion, fingerprinting, etc (Stalin's purges and the high turnover rate in the KGB would be good examples of structures that work well in compression but not in tension). This also rips apart nations based on differences of ethnicity if the tension stress is great enough as in the case of Yugoslavia and the term "Balkanization." There are other examples like the arbitrary ethnicity of the Hutus and Tutsis or the Hatfields and McCoys... once two institutions or group are found with a large amount of differences flavored with negative emotions for repulsion... the stress pulling at the sides is reduced in-order to tear them apart and the larger entity as a side effect. In school this can be seen as the mean girl effect (probably due to a region of the hippocampus that being lingering in social maps rather than spacial maps like males) to know exactly what a weak and sore point is in a group or person and tear the wound open. That said, it can work in reverse and strong materials tend be able to take a lot of tension (I just wanted to use reinforced contract as an example of the rock mix being good at compression but weak in tension which is solved by a network of high tension steel to keep it from cracking apart and collapsing)
-Sheer - When you combine both elements of stress you get a shearing most often seen with spinning rods (axles, camshafts, etc). It's an angular issue where a portion is compressed in one direction from one side and the kitty counter side is compressed in the opposite direction... with enough force the material will slide over itself like the fault lines rubbing and breaking the bonds in between. School shooter, domestic terrorists, or a guy going 'postal' could fall in this category or continually taking stress from different angles but not being tied into structures at large in a scapegoat fashion ('Joker' with the constant turning away or torques but few bonds save with weak ones, with Murray, his Mom, etc but as they snap... eventually he does and all that negativity blows out rapidly, strongly, and tragically... the stapler from 'Office Space' is a little less dark). The group is small and constantly spinning in the larger group with more successful examples being Jewish groups in Medieval Europe (many organized bonds) or a spec ops team (extremely modded and bonded elements) in hostile territory. Sebastian Junger's "Tribe" illustrates this issue with young males (as young females tend to take their own life then seek retribution on society) an using initiation/rites of passage techniques to bond the individual into a group to end the spinning (frats or masons but unhealthy groups like gangs could weld them to a larger spinning axle separate from the overall social structure) and share the stress in compression or tension depending on the group.
- Work of Fracture - There are so many gems in this book but this notion of a material being as strong as its weakest link is fascinating. Gordon uses 'stress lines' in tension on something like a strip of cloth. So long the material is intact and the fabric is held in tension equally at both ends (pulling with your hands) it obeys the normal strength rating. However, if you make a small cut in the side, it has the potential to rip across and split the strip in two. This has an overlap with polarization since all the stress lines (pulling) from the separated ends flow through the center point where the crack ends (a stress concentration). You can see this in groups with radical 'fringes' having a split divide on some issues but as the group grows, the tension they put on the moderate center grows... Once the sides are large enough they can rip across society with statements like "YOU MUST CHOOSE, YOU'RE EITHER WITH US OR THEM!" In the book, he highlights how the British Admiralty lost many metal ships with sharp cornered doors (smooth rounded corners or holes distribute stress lines better) in forces well below the rated tensile strength of the material but they didn't account for stress concentrations... similar to society. Finding and acknowledging this cracks (wedge issues, grievance, grudges, inequities) is double sided a Sith mentality could use them to divide and conquer for quick chaotic power over shattered pieces where as a Jedi approach of not blaming a side, trying to temporarily relieve the stress, and resonate with both sides to weld or mend the rift is much slower and more difficult but leaves the piece united and whole.
*Spanning the Divide with Thrust Lines - Societies, especially global ones, span extremely large distances with complexities and diversities that are increasingly linking across cyberspace but the stresses are extreme and the cracks numerous. Taking another cue from Gordon, older architecture had significant problems with roofs due to spanning large distances partly due to building materials, form and other factors. An example of 'two side' or rafters for the span is that they enclose and crown the structure but the pressure does not rest squarely on the walls and pushes outward toppling the walls in outward extremes under the weight of the roof and its thrust lines. So there are several options to take these outward pressures and make sure they push down vertically to make use of the wall/pillar's compression capacity without flipping them as a house divided by thrust lines can't stand.
-The Flying Buttress - Cathedrals in Europe use this method with pillars on each side butting against the top of the wall with arches (to smooth or angle the spreading force of the rafters) and are further capped with statues or spires on top to increase a downward vertical pressure with weight. This could be analogs to myths or role models that cap the extremes at both sides... like a AA member with a 20 year chip... ya he or she has given into that stress before (understanding the pressure to buckle), they've made it (social proof), they have stories of what buckling entails in the future or friends who buckled all the way (myths or stories), but the can support the extremes that rely on them if the group system and sponsorship links are in place... you could do the same with other reformed extremist's to buttress from the their side and not push from the opposite side which will further the buckling.
-The Arch - Stones are more akin to smaller social groups (more masculine) without reinforcing structures... They are great at compression from without but are liable to shatter as a beam under their own spanning weight as their close short bonds are not great in tension and form smaller groups. Both the Roman Arch and Legionary system (something the US military is modeled on) uses this system of taking mostly men, reforming them into members of team or voussoirs (slightly curved blocks) and putting them in a competitive interlocking structure. There is only compression and the group on both sides holds them in place or to a standard (squads to platoon, scale shift platoons to companies, etc). Each area shares a designated load in an area, the command structure discourages mob mentality and splitting (the french revolution fracturing in high tension and the ensuing blood bath), and the individuals (females as well) can share stress by giving each other 's***.' The individual has support from their sides and close connection from far away stress but also correction or being put back in one's place if they start to weaken (lying or puffing up as the members are always there and in moments of high stress to see if they're full of s***). When the group is one blob all the tension builds on fractures in the beam and once they grow big enough... snap... there are two separate ends and broken structure. Once male exclusive systems are pretty similar in the "hierarchy" as it pertains to sports teams in leagues, company's, fraternities, etc. as the competitive units compressing each other make the structure stronger over time as well as the units, and the elements in the units (people in the teams)... but also that no one group becomes a tension point for the whole to collapse on (though the book does note it takes four hinge points to collapse an arch so units do need repair or load limits).
-Trusses - Another way to keep the roof from separating is bridging it with a beam that can withstand the tension (not a get application for stone). On average is more of a feminine strategy and one that seems to get swept under the rug by always using the hierarchy (male competitiveness) and certain waves of feminism that seem to want to form women into men (adding new rights and privileges which is awesome but also a kind of baby out with the bathwater on money, career, competition, and objectivity as the only standard). Lydia Denworth has an illuminating observation on these female bonds in macaque societies that allow for the male competitiveness. Essentially the females are in ranked casts of lineages that are quite complex but their position is the social placement that doesn't change. The males have to leave their group (expulsion for incest reasons), and seek out another group, from there the male has to prove himself and that determines his mate and monkey office (similar to reinforced concrete, the males harden like cement around the strong female bonds or steel). Likewise, the average female mind (though there are fabulous fluid minds and more tomboy temperaments in the middle of the camel's hump). Perhaps it's controversial, but that girl time gossip that is more egalitarian seems to allow for most perspectives to be shared and come to a hive mind like agreement (females tending towards generalists that can take large, interlinked social networks and place males in positions where the can specialize, compete, and bond locally)... males tend to want to compete for their side or group to dominate (in general but also the narrative) and create structures that let them do so. Herman & Chomsky outline it in the "Manufacturing of Consent" where by one group has an issue and doesn't point it out or hides/silences it but will point out other groups (kind of like painting over rotten wood or a crack and calling it fixed but exposing someone else's rot or cracks)... Chomps seems to go the opposite way for balance in the use or charged language domestically and naturally when it's another (the 'granted') but I suppose that's necessary to drive home the point pre 911. This is another issue, and new testament quote, that makes it difficult to fix things here as it would mean admitting a mistake (and possible external application of pressure) almost impossible as it make one an enemy despite trying to solve the problem (like a wounded animal that's sick and infected but too leery to let anyone close to help as they could just as easily finish them off). Going back to social restructuring, there do not seem to be as many female egalitarian institutions to form a broad consensus with all sides like large groups in church, mosque, synagogue, temple, etc use to be able to do and busy working mothers have far less time and energy to pass on their knowledge and skills in group setting to their daughters (with the joys of social media filling the void... sarcasm intended). Granted (see), males (a large portion) do not want this egalitarian style and would fight it like a cat with mittens (the endless leg twitches) with cries of femnazi and the masculinization of women is making out society brittle (save for those inclined that way)... we have a complex society and it reinforcing it with strong general female bonds seems doable... rewarding motherhood with paid leave (maybe out of a fund for two kids) and providing social systems that could be expanded for mothers to congregate in formative years and for mock social setting of kids and large scale bonds to influence their husbands. The focus on career as top priority from consumerism and conspicuous signaling moving into social media goes too far in making male priorities female priorities when we specialize (with overlap and many multiple scales of polities from experience as well inheritance). In terms of Psy-warfare, females would have an advantage in being able to think in terms of people and not just thing (male advantages in spatial storage)... more so as a shield than sword as women's movements drove abolition, suffrage, stops to vivisection, prohibition (well intended but with too many side effects) but also in people oriented fields like education, medicine, and hopefully media in its many forms (unifying... the male perspectives still need to be heard but in a holistic framework). Yet more objective subjects could be rendered in narrative styles as opposed to mapped subjects written by males unknowingly for males (though there's overlap in brains opposite of sex and thus minds). Think about what happened when architecture was freed of only masonry and steel was blended in... with the right mix Social Engineering could be much more stable, integrated, and complex to stop conflicts before they start with feminine tensile strength.
A good book that aptly describe "Structures: Or Why Things Don't Fall Down".
It explains many structures: Stone Masonry, Suspension Bridges, Arches; Wood, steel, Stone as support structures; Tension, Compression of Materials; Lattices, Fracture Mechanics and many more. Through simple observation I'm sure people understand these concepts intuitively- Take fracture mechanics for example: You have one solid block of material like a wall- it requires a large amount of concentrated force to cause a small crack/fracture in that wall. However, once the initial crack is in place the material around the crack is subject to astronomically more tensile strain (in some cases 10,000 times the initial tension). This makes the next possibility of a crack more likely to occur in a domino effect. It also explains how stone walls collapse through the conversion of compression from stack stones to tension, which occurs on the sides of a brick. If you've ever seen old stone architecture you can see that the corners of stone appear shaved, this principle explains why this is so. It also explains why bodies can diffuse energy as soft tissue can rebound shape and dissipate energy through kinetic links while brittle materials like stone or bricks smash with a modest amount of force.
The last chapter tells us a few things about the energy consumption of materials like Steel: Steel was sustained to be developed due to an excess of high concentrated energy sources like Coal and Oil. Our obsession with steel isn't sustainable when we consider the energy needed to produce this so we should try to move to other materials that are net-free energy: Timber has very interesting structural properties like being lightweight, similar compression to Concrete, Elasticity and a high tensile Strength. There's a fair amount of formulas in this book so it's definitely useful for a structural engineer, slightly less so for a non-practitioner but the conception of ideas explained are very useful for mapping the world around you.
This book explains the engineering principles of mechanical structures to the public in an interesting approach that gives examples and case studies that are directly related to the human species experience in history and present. Although, the intent of such popular-engineering book is to simplify the engineering concept found in the field of mechanics of materials to the public, the author does not present the topic in a shallow manner. Besides the popular-engineering content that reflects the high exposure of the author to history, biology, mythology and literature — the book is continuously injected with engineering mathematical equations with curves that show the stress/strain distribution or behavior with respect to another parameters.
I believe that individuals who belong to engineering disciplines will find the book very interesting and probably entertaining. I would indeed recommend it to the highly devoted students or practitioners in the field of civil and mechanical engineering.
Highly recommend to anyone interested in learning more about how the infrastructure they depend on every day works or that is generally curious about the world.
This book is like a great course in college - you learn a lot, but the professor does a good job of tying it to real life examples, so every lesson is interesting.
If I told you the book was about structural engineering, you'd think that it involves a lot of math. Basically - don't worry about it. The author does not assume a lot of physics/math background and you won't want to take out a sheet of paper to solve anything to enjoy the book.
One of the better non-fiction books I've read in a while.