44 votes
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Why are engine blocks so robust apart from containing high pressure?

If you consider only the static forces then indeed the thickness might seem over-engineered. However, engine blocks are not statically loaded. They operate in the range of a few hundred to a few ...
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  • 22.6k
15 votes

Why are engine blocks so robust apart from containing high pressure?

You need to consider that the complete engine block has to withstand the reciprocating forces generated by each of the pistons and con rods moving as well as the rotational forces from the rotating ...
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12 votes
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Is it useful to stuff my glasses with newspaper to protect them?

In itself putting paper inside a glass will make very little difference. Glass is a brittle material and tends to fail by shock and point loading. Its static tensile strength is actually pretty good. ...
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12 votes

Why are engine blocks so robust apart from containing high pressure?

The vibration, loading, and fatigue aspects have already been addressed, but a wide range of operating temperatures is another factor. A typical consumer engine can be deployed in anything from say -...
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  • 221
11 votes
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What is the advantage of statically indeterminate structures?

For example, take a look at the following static systems. Assume they have the same length and the same (constant) cross-section. Thus an equal allowed bending moment $M_u$. The first system is ...
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  • 1,146
11 votes

What is the maximum angle of a shelf angled brace?

The angle is arbitrary. One can decide which angle is more practical. However, it comes at a cost: the more the angle from the vertical the more pulling and pushing force on the anchors or escrows. ...
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  • 20.9k
10 votes
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Why does a continuous beam have less deflection than a pair of simply supported beams?

For a simple visual demonstration, take one of the spans in your example. If it is fully hinged, then each span can be represented as a simply-supported beam. If the beam is continuous, then each ...
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9 votes
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General solution for the most critical pattern of live loading

As mentioned in the linked text and in @grfrazee's answer, the secret is influence lines. Or, more generically, influence surfaces. For starters, let's stick to influence lines, since they are far ...
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9 votes
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Do scaled models reflect strength characteristics of full size

Things scale, but not always in a nice simple way. For example consider the units of stiffness of part of the structure are $E$ (Young's Modulus) times some length, but the units of weight are $\rho$ ...
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9 votes
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PE exam: situations in which two question choices are close to my final answer: how to pick one?

You are worrying about the numbers and forgetting what the numbers mean. This is for the PE exam, so this is a very important topic to make clear in your mind. You solved the problem. You came up with ...
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8 votes
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How should one model a structural model with both line elements and area elements?

Say we have a slab supported on a beam. The centroid of the slab and the centroid of the beam are not coincident. Fortunately, in FEM software packages the geometric centroid of the element can be ...
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  • 2,770
8 votes
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What are the principles (if there are any) behind the conservation of bending moment in frame analysis?

Well, such an equilibrium (be it of moment, or shear or axial force) is necessary for any static system, and can be trivially demonstrated with Newton's second law. For forces, that is the classic $F=...
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  • 12.7k
8 votes

Is it useful to stuff my glasses with newspaper to protect them?

Filling inside the cup with paper is just to lock in the wrapping of the same paper around the glass. It also offers coverage and protection of the rim of the glass. Because of the integrated, all-...
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  • 20.9k
8 votes

Why not build container ships from plastic?

In short, because steel is less expensive on a strength per dollar basis of anything else, and for large structures, it's less expensive to work, again on a strength per dollar basis. That's why ...
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  • 2,208
8 votes

Increasing torsional-stress resistance of an Auger at its motor-shaft joint

As your construction is 3D printed, increasing the strength at the point of current breaking will more likely transfer the damage to a new location. The obvious and possibly impractical solution is to ...
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  • 6,102
7 votes
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How to derive Equivalent Static Load for irregular structure modeled with FEM?

The short answer to your question, How can we compute the Equivalent Static Lateral Forces, the overturning moment and other quantities in an irregular building/structural discretized by finite ...
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7 votes
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Interpretation of shear flow/shear center of L-profile

Firstly, the shear center is the point at which an applied load produces no torsion on the section. For a singly or doubly symmetric section, the shear center will lie on the axis of symmetry. For the ...
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7 votes
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Mathematical representation of hinge and pin connection

I believe you have chosen a poor reference. Indeed, that link has absolutely nothing to do with structural analysis, but rather a specific implementation in steel structures. A ...
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7 votes

Are abandoned nuclear smoke stacks strong enough to be filled with water (for pumped storage)?

Those aren't "smoke" stacks but cooling towers designed to let hot air rise and expand optimally. These things are typically 200 m high. Static pressure of 200 m of water is pretty high. They were ...
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7 votes

Why conduct experiment for load distribution within three triangulated structural frameworks when you can calculate theoretically

There are several general reasons for conducting practical tests in addition to theoretical analysis. to verify that the theoretical approach and associated assumptions are valid. Pretty much all ...
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7 votes

Why not build container ships from plastic?

Anything is possible and lowering the lightship weight (LS) of ships will save fuel, but the key issue would be any change must not reduce the seaworthiness of ships. This question is very broad. ...
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6 votes
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Determining the microstructure of steel after welding in modern computer software

Summary: 1) The answer to this question is difficult. You would need to know how austenite and ferrite behave in relation to what you are doing to them. You would also need to know their compositions,...
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  • 3,971
6 votes

How do you check a weld for applied moment?

What chapter/section of AISC codifies this kind of problem? If you're looking for a specific code provision for this exact type of weld, you're out of luck. However, it is possible to solve this ...
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  • 3,587
6 votes

Accidental Torsion and Equivalent Static Load for an irregular structure

How should we obtain $F_x$, given that it is lateral static force, but we are doing dynamic analysis? $F_x$ is the sum of the lateral force for a story. If you've performed a dynamic analysis, ...
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6 votes

What does it mean when actual member reaction is 100% of allowed?

This means that the member is considered to be fully loaded for a failure mode which is being analyzed by that stress calculation. Some things to (probably) keep in mind include: Some conservatism ...
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6 votes
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Why the design of continuous beam is always more economical than beam with supports?

I see another answer has given input on the strength side of things, where the economics isn't as clear, so I will add that one of the crucial aspects that usually make continuous beams economical is ...
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  • 318
6 votes

What is the maximum angle of a shelf angled brace?

There is no maximum angle. Theoretically a shelf could be supported solely via cantilever (a support coming straight out from the wall. If the angle in use is the angle from the wall to the support, ...
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  • 4,408
5 votes
Accepted

Steel Roof Truss Shape Question

This looks like a Collar Beam Roof (or sometimes a Collar Tie Roof). It is often used in lightly-loaded residential construction. One popular use is to form Cathedral Ceilings. Strictly speaking this ...
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  • 2,631
5 votes
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Can I reduce the column moment due to beam, by setting the beam end to pin?

Yes this is correct - if you want to eliminate the moments in the columns then a pinned connection between the beam and columns will achieve this. To demonstrate this I have recreated your structure ...
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  • 1,217
5 votes

Can I reduce the column moment due to beam, by setting the beam end to pin?

As @pauloz1890 has already stated in his answer, if you add a hinge to a beam-column connection, you will eliminate the bending moment on your column (assuming no horizontal loads are applied). That ...
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