Engineering Ethics: Crash Course Engineering #27
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Date: 2022-04-04
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Comments and reviews: 10
EngiBear
-No no no no no. The script has made the same mistake as the Hyatt Regency walkway design engineer! The tension rod was always supposed to support both walkways. The problem was that the revised connection detail passed the load from the lower walkway through the HOLLOW BEAM and through its connection to the upper rod rather than directly through a continuous single rod (which was still a bad design, because it couldn't be physically put together as shown on paper, hence the revision. The top rod was fine, but its connection to the hollow beam section was exposed to roughly twice as much load as originally designed for, and it was torn out of the wall of the hollow beam. That's the textbook version, anyway. There were probably some other mistakes, too. -
-Ad hoc illustration for the layman: Imagine a vertical meter stick punched straight through two paper towel roll tubes, with one near the middle of the stick and one near the bottom, and glued to the tubes where it is punched through. Imagine what would happen if you pulled hard on the ends of the meter stick. Now imagine the meter stick is sawed in half right below the first tube, punched back through it a few centimeters away from the first hole, and again glued in place. Now what happens if you pull hard on the ends of the stick? -
-It should be noted that Thought Cafe's animation looked pretty correct in this case in spite of the script. Some of their other depictions of structural behavior in this series have been unintentionally misleading. Which is understandable. Professional animators can't also be professional-everything-elses, and most people don't have the budget to just faithfully draw every single object based on a real-world model, so unintentional impossibilities always creep in from the artist's imagination. (Stone masonry ceilings, bridges, and lintels set in a historical context but imagined by an artist who grew up in a land of steel and reinforced concrete structures are HUGE offenders) But it's also unfortunate. Accurate pictures are key to understanding engineering concepts. -
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-No no no no no. The script has made the same mistake as the Hyatt Regency walkway design engineer! The tension rod was always supposed to support both walkways. The problem was that the revised connection detail passed the load from the lower walkway through the HOLLOW BEAM and through its connection to the upper rod rather than directly through a continuous single rod (which was still a bad design, because it couldn't be physically put together as shown on paper, hence the revision. The top rod was fine, but its connection to the hollow beam section was exposed to roughly twice as much load as originally designed for, and it was torn out of the wall of the hollow beam. That's the textbook version, anyway. There were probably some other mistakes, too. -
-Ad hoc illustration for the layman: Imagine a vertical meter stick punched straight through two paper towel roll tubes, with one near the middle of the stick and one near the bottom, and glued to the tubes where it is punched through. Imagine what would happen if you pulled hard on the ends of the meter stick. Now imagine the meter stick is sawed in half right below the first tube, punched back through it a few centimeters away from the first hole, and again glued in place. Now what happens if you pull hard on the ends of the stick? -
-It should be noted that Thought Cafe's animation looked pretty correct in this case in spite of the script. Some of their other depictions of structural behavior in this series have been unintentionally misleading. Which is understandable. Professional animators can't also be professional-everything-elses, and most people don't have the budget to just faithfully draw every single object based on a real-world model, so unintentional impossibilities always creep in from the artist's imagination. (Stone masonry ceilings, bridges, and lintels set in a historical context but imagined by an artist who grew up in a land of steel and reinforced concrete structures are HUGE offenders) But it's also unfortunate. Accurate pictures are key to understanding engineering concepts. -
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Master
This reminds me of a lecture I had when I was a physics undergrad. It was an odd lecture in our Thermodynamics and structure of mater course. Our lecturer stood in front of us and began lecturing on several structural engineering failures (chiefly the dehaviland comet and an under inspected railway in England) and I will remember the speech he gave at the end It went something like -as physicists you will be faced with points in your life where you will faced with opposition to doing what is scientifically right by powerful interests both political and/or industrial. When this happens I hope you act in the right way because these people who issue these demands will very rarely be held to account but you will. Not just by any investigations but by yourself and by your fellows in your field of work. I hope you make the right choice because you will have to live with it otherwise and maybe more importantly others may not. -
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This reminds me of a lecture I had when I was a physics undergrad. It was an odd lecture in our Thermodynamics and structure of mater course. Our lecturer stood in front of us and began lecturing on several structural engineering failures (chiefly the dehaviland comet and an under inspected railway in England) and I will remember the speech he gave at the end It went something like -as physicists you will be faced with points in your life where you will faced with opposition to doing what is scientifically right by powerful interests both political and/or industrial. When this happens I hope you act in the right way because these people who issue these demands will very rarely be held to account but you will. Not just by any investigations but by yourself and by your fellows in your field of work. I hope you make the right choice because you will have to live with it otherwise and maybe more importantly others may not. -
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CK
NO PLEASE, CHECK YOUR SCRIPT, the rods don't take more load, it's the connections.
The rods carried the exact same load in both design cases. Therefore the rods itself were correctly designed to the correct sizing to carry the loads intended
The problem there is the joints/connection of the top walkway with the two rods. The connection to the upper rod carried double loading, not the rod itself.
If 100 people still don't understand I'll make a short video explaining it in layman's terms.
I know this might seem small/useless correction to a crash course video. BUT any error, no matter it's magnitude, is an error. Small errors can cause the worse accidents imaginable.
(Facts must be told correctly, else I will hear some uninformed person convinced that those poles were too small, and even after proper engineering explanation, they would still not believe the truth)
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NO PLEASE, CHECK YOUR SCRIPT, the rods don't take more load, it's the connections.
The rods carried the exact same load in both design cases. Therefore the rods itself were correctly designed to the correct sizing to carry the loads intended
The problem there is the joints/connection of the top walkway with the two rods. The connection to the upper rod carried double loading, not the rod itself.
If 100 people still don't understand I'll make a short video explaining it in layman's terms.
I know this might seem small/useless correction to a crash course video. BUT any error, no matter it's magnitude, is an error. Small errors can cause the worse accidents imaginable.
(Facts must be told correctly, else I will hear some uninformed person convinced that those poles were too small, and even after proper engineering explanation, they would still not believe the truth)
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Garret
The upper rod was going to hold the weight of both floors in both designs. The actual difference was in the force supported by the nuts. The nuts in the design change need to support two floors and the lower rods, the nuts in the first design only need to support the second floor.
Important note for this: the design change still actually met the normal weight requirements of the walkways, the party on the day it failed put the hotel over the occupancy limit, meaning the original design had enough factor of safety for all situations but the change did leave it open to fail only under this situation: massive bangers.
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The upper rod was going to hold the weight of both floors in both designs. The actual difference was in the force supported by the nuts. The nuts in the design change need to support two floors and the lower rods, the nuts in the first design only need to support the second floor.
Important note for this: the design change still actually met the normal weight requirements of the walkways, the party on the day it failed put the hotel over the occupancy limit, meaning the original design had enough factor of safety for all situations but the change did leave it open to fail only under this situation: massive bangers.
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Mathieu
Correction - The Oring on the Challenger booster did not fail due to an issue with the oring itself but the fact that NASA decided to launch when it was too cold for the oring to do it's job. The booster had NEVER been tested that cold, and the specifications for the booster did not allow for a launch that cold. Ultimately NASA launch control killed those people not the Engineers.
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Correction - The Oring on the Challenger booster did not fail due to an issue with the oring itself but the fact that NASA decided to launch when it was too cold for the oring to do it's job. The booster had NEVER been tested that cold, and the specifications for the booster did not allow for a launch that cold. Ultimately NASA launch control killed those people not the Engineers.
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Dan
As stated before, Ethics are seldom taught or discussed in Engineering. In real industry and even in Academia it is more often than you would expect not complied. The goal of Engineering is to make money and that is what industries are about. Ethics maybe come in 10th place, after Safety, Problem Solving, Environmental Protection etc etc.
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As stated before, Ethics are seldom taught or discussed in Engineering. In real industry and even in Academia it is more often than you would expect not complied. The goal of Engineering is to make money and that is what industries are about. Ethics maybe come in 10th place, after Safety, Problem Solving, Environmental Protection etc etc.
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E172-7N
Im 16 years old and going to build an ultralight aircraft around 50kg. I will make a electric motor with copper wires and run it with dc power supply. I will use under cambered aerofoi and rectangular wing. I will design a pulley system for control surfaces. There will be some calculations with Cl-Ct-Cm
All I need is a carpenter.
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Im 16 years old and going to build an ultralight aircraft around 50kg. I will make a electric motor with copper wires and run it with dc power supply. I will use under cambered aerofoi and rectangular wing. I will design a pulley system for control surfaces. There will be some calculations with Cl-Ct-Cm
All I need is a carpenter.
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imsoolazy1
This is the first video I've watched in this series, and the speaker is great but the editing is downright weird. The jump cuts between different angles of her face while she is speaking is very distracting.
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This is the first video I've watched in this series, and the speaker is great but the editing is downright weird. The jump cuts between different angles of her face while she is speaking is very distracting.
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wandyezj
It might be worth mentioning that a sub optimal (used O Rings) design was chosen in the first place because of politics (congressmen wanted money to be spent in their district.
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It might be worth mentioning that a sub optimal (used O Rings) design was chosen in the first place because of politics (congressmen wanted money to be spent in their district.
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jedigecko06
There's an episode of 99% Invisible on ethics and prison engineering. (Does the designer have a duty to the inmates _separately_ to the institution)
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There's an episode of 99% Invisible on ethics and prison engineering. (Does the designer have a duty to the inmates _separately_ to the institution)
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