Questions tagged [structural-analysis]

Structural analysis is the determination of the effects of loads on physical structures and their components. Structures subject to this type of analysis include all that must withstand loads, such as buildings, bridges, vehicles, furniture, soil strata, prostheses and biological tissue.

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311 views

Why not build container ships from plastic?

This may sound crazy but bear with me. I was thinking about why cargo ships are built from such heavy material as steel, while smaller boats are often made of plastics. I know cargo ships carry a lot ...
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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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Should the corbel angle always be estimated as 60 degrees in masonry construction, or is there a formula to use instead?

In educational construction material as well as engineering publications, the corbel angle for significant excess loads, and also for substantial openings, in an ordinary brick wall is usually ...
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Why do stress concentrations really occur?

From doing some research I've learned that internal stresses inside an object can "concentrate" on sharp edges, as shown in the above picture. For that reason we often make fillets so that the change ...
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29 views

Why would a SMD (spring mass damper) model of steel break down?

Under what conditions would steel be able to be modelled as a 3D SMD model, and under what conditions would the model break down?
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Rotational and translation DoFs in structural mechanics

I'm a computational person, and I don't quite understand how rotational DoFs are manifested in the linear elasticity equations. I understand the translational DoFs are simply the displacement ...
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1answer
526 views

Member weight in a planar truss?

So I'm given a question in which a Truck drives over a pratt truss bridge. In the question the truss is in 3D. I'm given: 1)The loads from each axle of the truck 2)The weight of each member in the ...
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1answer
49 views

How to allow only one mode of resonance in a cantilever beam

So I am designing a MEMS structure consisting of cantilever arrays. For my problem, I want the cantilevers to vibrate only at their 1st mode of resonance and reject all the other modes of resonance ...
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77 views

Analytical calculation vs FEA

In terms of calculated stress, strain, displacement etc which method yields more conservative results. Analytical calculation or numeric calculation?
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239 views

Honeycomb structures vs shear stress

Honeycomb structures are made of top and bottom shells and honeycomb geometry at core. In terms of bending load, maximun normal strains take place on top and bottom hence, sheet parts can support them ...
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1answer
29 views

Drucker-Prager Model Parameters, a Proper Choice

My task is to write a code from scratch for 3D elastoplasticity, namely a DP model (see for example DeSouza Neto, et al., 2008, Chapter 8) having yield surface $$ f(\mathbf{\sigma},c) = \sqrt{J_2(\...
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Possible improved approaches to 6mx3m moment-resisting frame with eccentricity+torsion, in advance of detailed engineer discussion

I'm putting a steel frame in, to "open plan" the rear of a brick cavity-wall terrace house in the UK, which will then have a single storey extension added behind it. I have already retained a ...
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29 views

Displacement of Gaussian point after structure simulation

When we did the simulation, we would get deformation and got each nodes displacement. In physics, it shows the trajectory of a system of particles of the objects. Is it the same as the displacement ...
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1answer
65 views

defining the dimensions of a bucket elevator chain link

how to define the shape of a heavy duty chain link when the pitch of the chain and the traction load that the chain is subjected to is known? lets say i consider the traction load as the maximum load ...
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Material for car mounted fire extinguisher bracket

Don't try this at home. I am taking personal responsibility for what happens in my car. Hi all, I recently purchased a fire extinguisher for my car (it weighs 1.5 lbs or 0.68 kg). I browsed the ...
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1answer
181 views

Calculation of natural frequency in a hinged beam

What I tried: Using the conjugate beam method to find deflection and hence stiffness of the beam, but I am unable to find reactions in the conjugate beam.
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Impact capacity of tension cables, columns and foundations

A rock is falling from an embankment of mass $m_a$ at a height of $h$. Below, a fall protection fence catches the rock, dissipating the energy through tension cables to steel posts and then into ...
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1answer
22 views

Supporting flexible square plate of uniform density in equilibrium with only 4 rolling contacts placed along the square's diagonals

Consider a flexible square of uniform density with vertices (0,0), (0,1), (1,0), (1,1). I need the 4 coordinates for rolling contacts along the diagonals that will stably support it. Someone could ...
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1answer
782 views

How is Load Transferred in a fully supported base

Suppose, you put a point load on a plate that is completely supported. The pressure under this plate is Force divided by the area of the plate. If I make this base very large, then pressure will be ...
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2answers
100 views

Analizing Vibrations Influence on Dynamic Weighing

I have a very sensitive scale used for dynamic weighing (by dynamic I mean that the scale and load cells are actually beneath a belt conveyor that actively weight product when it´s being transported ...
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1answer
84 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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1answer
135 views

stress/shear analysis of components

I am working on analyzing a few problems, but have not really come across this type of stress concentration problem. Does anyone know where I can study the analysis of this situation? Pressing ball ...
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1answer
117 views

Stress Tensor decomposition into Compression & Tensile forces

I'm working on a project that does a finite element simulation of a mesh. I can output the stress tensor at each node, but I'm not so sure how to implement failure criteria. If my material is brittle,...
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2answers
166 views

How to calculate stress in a cylindrical-uniaxial-loaded bar with sudden changes in its diameter

How can I calculate the von Mises stress in the cross-section of a bar like this that is axially loaded?
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48 views

STEEL CONNECTIONS

Hi, so, would you consider the connection detailed here as fixed or pinned during your structural analysis?
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1answer
195 views

Portal frame stability

Is there any way a portal frame with pin joints at the top of the columns can be stable? Are portal frames ever done with pin joints at the bases? (Aside from those with raft foundations/combined ...
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104 views

Analysis method for two-way slab floor with central column

What method would be appropriate to analyze this concrete structure? A two-way rectangular concrete slab with walls and central column. I would like to understand how to model it with either yield ...
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Most efficient way for finding the rotation angles after moment distribution (Cross method)?

First of all, I have taken a look at the Grinter's method, which is similar to Cross, but balancing angles instead of moments. My question assumes that we are using the Cross method, and not the ...
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1answer
59 views

Normalizing the compressive stress to a cylinder

I'm not an engineer but a neuroscientist. I do research in spinal cord injury whereby a clip is used to clamp the spinal cord to induce a bilateral compression injury model. My research looks at the ...
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1answer
221 views

Stiffness as a function of thickness

Let’s say we have a thin band (made out of PLA, 3D printing material) with a rectangular cross section. In drawing, it would look something like this: Let’s say a force of 15 N is to be applied from ...
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1answer
943 views

Percentage area of steel for a retaining wall - standard formula doesn't make sense to me?

I'm looking at the usual UK/EU standards formula for the reinforcing steel area percentage, in a retaining wall. Essentially in "usual" cases it comes down to 0.13% of the cross-sectional area of Tw (...
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1answer
691 views

Natural frequency of a column + mass

Consider a system made of a cylindrical column (fixed on the ground) with a mass attached on top of it (B). Both the mass of the column and the mass are not negligible. Depending on the value of the ...
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1answer
486 views

Can secondary beams be supported to columns occaisionally?

If there are secondary beams running between primary beams, and columns support the primary beams, then is it allowable to have the occasional secondary beam pinned to a column? Otherwise it seems to ...
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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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2answers
44 views

What is the 'application standard' referred to in EN 1993-1-7

I'm using the Eurocodes for some structural analysis and am looking for the limiting value of deflection of a plate. EN 1993-1-7, Section 8.2 states: For limiting values of out of plane deflection w ...
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1answer
100 views

What diameter aluminum pole do I need to lift 100 lbs vertically?

I am wanting to use an aluminum pole (as a Jin Pole) to lift the mast on my sailboat into place. My mast is about 30 ft. long and weighs between 80 – 100 lbs. The aluminum pole would be stood ...
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2answers
773 views

Neutral axis in canteliver beam at support

First, I thought the neutral axis would just be the y bar which can be obtained from the centroid of the cross-section but is different. I have tried letting the net moment at the wall = 0 and the ...
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1answer
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Someone please explain how to get the FAx and FEx because both support are pin.. I only got the FAy and FEy

Can someone explain how to get the Fx for the support A and E
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1answer
80 views

Understanding plastic deformation

Is understanding tensors a prerequisite for understanding plastic deformation (metal forming) equations, plane stress, plane strain conditions, etc..? If so which book should I use to understand ...
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1answer
202 views

FBD of folding table leg

I've drawn an FBD of one leg of the table the picture. I've a feeling I'm missing something. Am I?
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1answer
67 views

Stress analysis for the same configuration but different material

The same geometry and the same free body diagram. However, if we replace the material from steel to glass, for example. How does that influence the analysis? Two things I think are 1. steel is ...
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1answer
100 views

How to model a UDL over a plate for bending?

If I have a square plate of height h supported along one side (an L-bracket, modeled as fixed support), and there is an evenly distributed force acting over the face of the plate. From load analysis I ...
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3answers
2k views

Minimum thicknesses of an elliptical cylinder pressure vessel

For pressure vessels in the shape of circular cylinders, we can use $\sigma_{hoop}=\frac{pr}{t}$ to find the minimum skin thickness by setting the hoop stress the maximum allowed value, and then ...
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340 views

Solar Array Frame Design / Statics Design Problem

I need some help with a statics design problem. I am tasked with designing a solar panel frame to mount on a building and am the only engineer on staff so I don't have anyone else to ask the simple ...
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1answer
721 views

Shear strength polymers

I was looking for some shear strength properties of common polymers/plastics.... I have not found any usefull information yet. I know polymers aren't that linear elastic, but I expected to find some ...
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0answers
81 views

How to join two beams rigidly?

Hi I am making a beam model using Abaqus. There are two beams created. I wanted to join two beams rigidly in the connection to transfer moments between beams. However, I do not know what connector or ...
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1answer
360 views

Strain gauge placement to measure a twisting beam

Where is it best to place a strain gauge to measure the twist of a beam? And what type of gauge is best? In my application, I have a small metal part which experiences a twisting and bending force. ...
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4answers
409 views

Is there any need to consider loading sequence in construction stage for structure analysis?

Load sequence in phases can be considered applying the self-weight load only to the story added in the appropriate phase. Assuming that the material will not go into yield stage ( will always be at ...
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1answer
51 views

Is it true that if the structure damaged or corroded, the stress will be lower?

I am comparing the stress results between original or non-corroded model to corroded model. I found that the stress value in non corroded model is lot more bigger than the corroded model, is it ...
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1answer
134 views

How to calculate residual strength of a corroded structure from their stress values?

Currently, I have an actual entire corroded bridge model in the FEM analysis in Abaqus I want to estimate the residual strength of this bridge due to corrosion from the output results in the Abaqus, I ...

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