Structures
L.E. Gordon
“The entire physical world is most properly regarded as a great energy system: an enormous market-place in which one form of energy is for ever being traded for another form according to set rules and values.”
What I like
Complex engineering topics are made easy to understand
Nice and engaging stories akin to “Set Phasers to Stun”
A good balance of practical engineering best practices and math, and design/engineering theory
What’s missing
It’s from the late 70’s so I imagine the rules have changed a little since it was written- so maybe a new edition would be warranted.
I struggled to understand some formulas introduced for concepts like Young’s Modulus
Key Topics
Engineering, Physics, Energy, Design, Aesthetics, Product Durability, Systems Thinking
Review
I originally learned about this book when researching book recommendations from Elon Musk, who I was interested in learning about since he is an infamous figure in technology and now politics. I work with Engineers, but know nothing of their language or what is meaningful to them, so this book felt like a good opportunity to explore a new topic.
After reading this book I have come to appreciate the relationship between engineering and aesthetics. In essence, Engineering is what makes an engine tick, as ugly as that system or process might be. Aesthetics are what protect the insides of an object from the outside world and make them interesting or attractive to look at. Much like the stem of a sunflower and its beautiful golden crown protect many intricate, less appealing, systems within it from the world around it. Engineers concern themselves with the durability of a product and its capacity to be resilient against the outside of environment. Engineers use measurements of Stress (molecules being pushed together) and Strain (molecules being pulled apart) to understand the amount of Force that an object can endure.
I did struggle to understand some of the more complicated topics and formulas in this book, and will likely need to read a few more times to better grasp this book’s contents. I would also be curious about how this book, which is centered around tangible things, would expand to a software Engineer. All that said, I learned a lot from Structures, and think that anyone who is interested in what Engineer’s think about should read this book.
Learnings
Organic structures are the most flexible and expansive and have allowed organisms to survive by shielding precious chemical reactions inside of them from the outside world.
Elasticity is the theory that whenever an object has force applied to it, its molecules will restructure themselves to provide an equal amount of force back- this action is called deflection.
Stress and strain are two concepts that are used to help understand how strong a material is. Stress can be calculated by the equation pressure (or load) / area. And strain can be calculated by the equation extension under load / original length.
Solids distribute stress evenly across themselves when stress is applied in an area. This causes strain as the solid’s molecules adapt to account for the stress, which is called a defection.
Resilience may be defined as the amount of pull that an object can take from the environment without changing from its original state. Or, in Engineering terms: the “amount of strain energy which can be stored in a structure without causing permanent damage to it.”
Nature and engineering have both used cylindrical or spherical systems where tensile stress or pressure is abundant, such as bladders, balloons (spherical) or pipes (cylindrical).
The purpose of joints is to transfer stress or load from one object to another. There are many different ways to create a joint between two objects, such as welding, which unifies both objects together and allows for stress to be better managed.
Elastic fibers such as veins or arteries were designed by nature to be able to expand and contract based upon pressure that’s applied to them without bursting.
The purpose of joints in a structure are to distribute load across various parts of a structure somewhat evenly. You can draw a line to show how load is distributed across joints which we can the thrust.
Hogging and sagging are two byproducts of tensile or compression stress being imbalanced across a structure. Hogging is when a beam, for example, flexes above the two supports that is attached to.
Shear, like Stress or Strain, involves the manipulation of an object’s molecules, and causes one plane of an object to slide against another.
When materials like beams are vulnerable to buckling due to compression, tension, or shear, stress, we should implement ribs, stringer, sandwich, or combination of the three to help resist buckling.
Aesthetics are a means of protecting the object and making it fun or nice looking by hiding the outside of an object from the complexities and ugliness of what is inside of it so that the viewer or user does not see it.