Questions tagged [structures]

Questions relating to or the engineering application of a device that must withstand a loading via deflection, stresses, resistance to buckling, or natural frequencies.

32 questions with no upvoted or accepted answers
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72 views

Normal stress - shear stress pairs not lying on Mohrs' Circles

The three Mohr's circles depict all the possible normal stress / shear stress combinations when material is taken and rotated along one of it's axes of principal stress. Nevertheless, it is clear that ...
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0answers
53 views

Hencky nets/slip-line fields on the the interior of a closed domain

This is a crossed post. The equations for Hencky nets are usually solved in the exterior of some domain; typical examples are the upper half plane or the exterior of a circle. I would like to know ...
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4answers
100 views

Bending moment calculation

Considering all the variables are the same, how to rank these connections from highest to lowest bending moment?
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0answers
26 views

Help sizing of lug attachment flange/plate?

Apologies for the crude drawing attached, but here goes. Given Fx, Fy, and Fz loads applied at the lug hole, I've distributed the loading into each of the 6 fasteners to size them. I've also sized the ...
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3answers
81 views

How many support beams/rods needed for a firewood storage cabinet

I am building a firewood storage cabinet which should support around 100-150 kg of firewood. The cabinet is made out of wooden boards (...
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0answers
28 views

When settlement criteria of a foundation is satisfied, bearing criteria is also automatically satisfied?

We design the foundations to settlement criteria than bearing correct? Because settlement criteria is stricter? I mean, can there be an example where the settlement criteria is satisfied but bearing ...
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0answers
19 views

Secure loads to gearbox shafts

I have a sculpture that is designed to rotate over 3 axes at max. 30RPM and is mounted on an aluminium disc. My plan is to use 3 of these geared steppers and secure the sculpture to the Z-axis shaft, ...
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0answers
198 views

Calculating diameter of steel rod required to not bend over a given length

I want to use steel (or other material) rods to support weight over a 900mm cavity. The weight that needs to be supported is technically unknown, but I'd specify some rough guidelines as: 100KG (max) ...
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0answers
34 views

What does 'Analysis Model Value' in NASTRAN optimization mean?

I am new to MSC NASTRAN and PATRAN. I am running a simulation on composite laminate optimization. While creating the design variables for the study, I noticed that there is a parameter called '...
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0answers
68 views

Calculating the Structural Forces Required to Support a Robot on an Overhanging Beam

this is my first time posting on here and I have a question regarding the structural properties a beam will need in order to fulfill some requirements we have for our robotics team. The scenario is as ...
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0answers
421 views

Beam element stiffness matrix for variable area cross section with mass and shear center not coinciding

I would like to find the full (12 by 12) Timoshenko beam element stiffness matrix for a variable cross section with mass center axis and elastic center does not coincide. I have the full stiffness ...
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0answers
32 views

How to support height extender on a rail?

I've got an 1/8" thick steel rail with 1.5" diameter and 15' in length sitting on two 5/32" thick steel rails with 2.5" diameter and 100" in length 14' apart: I want to add a diagonal support for a ...
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0answers
39 views

Check of a nominaly pinned steel joint

I am interested how to check a nominally pined joint. Especially how to check its rotational capacity and whether i can define it as nominally pinned in structural fem model. I understand that there ...
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0answers
27 views

How to calculate a global strain from a field disitribution

For an arbitrary articulated structure subject to non-affine (non homogeneous) deformations, the components of the strain tensor are defined locally. Is there a way to calculate a numerical strain ...
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0answers
1k views

best way to reinforce existing structural header?

House remodeling. I need to enlarge (from 7 to 10-12 ft) and shift (about 5ft sideways) an existing header where one passes between rooms. On one side, the header has 2x8 ceiling joists nailed to ...
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0answers
9 views

Question regarding 2D simulation of orthogonal cutting operation on Abaqus

I'm trying to simulate an orthogonal cutting operation on Abaqus, I'm using Dynamic explicit analysis. I have defined my tool as Rigid analytical body and the workpiece is of Ti6Al4V, I have not ...
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1answer
60 views

Is it possible to use Plain Cement Concrete post for fencing?

I am in need of around 700-800 posts to fence my farm in a semi-arid area in TN state, India. In my place granite posts mined from quarries are normally used. It costs around Rs 300-400 per post(6-7ft)...
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0answers
19 views

Wind behavior and pattern

From the 5 options, which one shows the worse wind effect? Is it (b) because wind speeds accelerate through a gap? But how about in comparison to (c)? Or (d) due to the height and sharp corners? If it'...
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0answers
52 views

Do any roller coasters actually use the brachistochrone curve?

Not sure if this is the right place to ask this. But I'm assuming roller coasters are related to engineering. I know that in theory, the brachistochrone curve is the fastest way from point A to point ...
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0answers
360 views

Deflection Of Beam In Structural Rigid Jointed Frame

This is a recommended follow on to one of my previous questions. It was stated that I could find the deflections of a beam by idealising it as a simply supported beam and then calculating accordingly. ...
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0answers
69 views

Need help with FEA bar analysis problem

I'm trying to solve this which is to find the total deformation of the bar. I'm trying to implement the finite element approach, but I am getting way too large of numbers. Here is what I did in ...
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1answer
83 views

Optimal method of attaching commercially-available heavy bag mount to finished ceiling with least risk of structural damage

Admittedly, this question is related to an earlier one on the same subject. I would like to mount a heavy bag using a system detailed in the attached picture (FirstLaw Fitness Shock Mount). The ...
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1answer
85 views

A Steel post and base question

I make solid curved wood furniture and frequently need something like a metal plate (1/8") with a (3/4" about) supporting pipe attached at 90 degrees. Welding is a little too cumbersome but I was ...
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0answers
34 views

Independent constraints - Procedure to verify it

I am wondering if there is a procedure to verify that the constraints of a system of rigid bodies are independent. Here there is an example of a system with dependent constraints: L beam - Strange ...
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1answer
86 views

compression buckling under lateral load

I'm trying to figure out what size of round tube to use for a tensegrity structure that'll probably have people climbing on it. The rigid elements are 21' steel tubes, and in normal cases they ...
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2answers
78 views

Beam/column sizing

If a load P is applied as shown to a fixed column-beam, pinned at the bottom, should the beam or column (or both) sizes be increased to resist the load?
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1answer
30 views

Shear connections

Question: which of the three shear connections (beam/column) below will require diagonal bracing?
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1answer
40 views

Method of joints not working on simple truss, supposed to be stable and determinant

In the process of editing the question to put better pictures of my dimensions in, I realized that how I calculated my angles was incorrect, and that is why my answers were yielding inconsistent ...
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1answer
152 views

What is the strongest structure?

I am not an engineer, but I thought maybe this could be a very old and classic problem in structural/mechanical engineering. I need to build a support structure to hold a uniformly-distributed load of ...
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3answers
46 views

How to solve a system of second order ODE from time t = T to t = 0

I have a system of second-order ODEs $$ \mathbf{M\ddot{x} + C\dot{x} + Kx = f} $$ I want to know some good numerical methods to solve this system of the equation given the initial conditions at time $...
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1answer
60 views

Flexure Deflection - Both ends fixed (one translation free)

I have a flexure problem. One of its ends is fixed to a frame (say F1) which is stationary (no rotation & no translation) and the other end is also fixed to another frame (say F2) which can move ...
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1answer
56 views

Wood Dimensional Stability

Between Glue Laminated and steel plate sandwiched between two wood beams, which one is more dimension-ally stable?