# 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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### Stress divergence of elastically deformed body is not zero

TL;DR According to the analytical solution (link) for a deflection of a cantilever beam $\sigma_{xx} = - \frac{P xy}{I}$, $\sigma_{yy} = 0$ and $\sigma_{xy} = -\frac{P}{2I}(\frac{D^2}{4} - y^2)$ and ...
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### Bar fixed at one end at heated

Consider a bar which is fixed at one of the ends. I increase the temperature of the bar by $\Delta T$. The sources I'm referring to say that stress developed in the bar will be zero because the bar is ...
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### Why stresses develop during non-uniform heating and not during uniform?

Consider a block of dimensions $l, b, h$ kept on a frictionless surface, initially at some uniform temperature $T_i$. Assume the material to be homogeneous and isotropic. When the block is heated ...
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### How to apply restraints on member which is on grade (continuous support)?

ETABS has option for providing restraints on joints, but how does one provide restraint to an entire member which is supported by ground ?
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### How does one conclude that the beams in this problem will be inclined?

I was practicing some problems of axially loaded members in Strength of Materials, when I stumbled upon this one: Two initially horizontal beams connected by aluminum and copper wires. Both the wires ...
28 views

### Calculating member stress in a truss

I have the following question: Here is my attempt: Is this correct ?
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### How do engineers conceptualize "levels of analysis" (thermodynamic, fluid dynamical, mechanical, etc.)

In considering something like a jet engine, the thermodynamic analysis can be very mathematical and quite simple (e.g. one-dimensional flow). It's quite general and takes exactly the same mathematical ...
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### FEM boundary problem in structural mechanics

I have spent way too much time in the last weeks/months implementing and writing my own finite element solver from scratch. I successfully implemented 2D and 3D elements and wanted to verify a few of ...
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### How do I calculate the total force required for a linear actuator? [closed]

How do I calculate the total forcerequired for a linear actuator? The image enclosed shows a series of door panels, each with a cam that i would like to connect to a linear actuator on the right hand ...
45 views

### Bearing stress in Bolts

Consider the arrangement shown below. It consists of a bolt, clevis and plate. Since, the clevis and the plate press against the bolt, the bolt will be acted upon by forces 1,2,3 (as shown). There is ...
44 views

### Double Integration Method

How can I solve this beam. I was able to find the moments of each section, from there I need help. Please if someone could help me. The method to use is Double Integration.
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### Homogeneous materials and direction dependence of properties

A homogeneous material is a material which has a uniform composition throughout. What do we mean when we say "uniform composition"? I have learnt about pure substances in Thermodynamics ...
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### A problem with quantifying ductility of a material

The textbooks I'm referring to for studying strength of materials say that we can quantify ductility using percentage elongation or percentage reduction in area up to failure point. The higher the ...
37 views

### Why does it take lesser iterations for a stiffer model in my FEA than a less stiffer model to converge?

I am currently using ANSYS FEA software and I conducted a simple geometric non-linear analysis of two same shaped bodies, but different cross sectional areas; one being quite bigger than the other. We ...
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### Help with understanding bending moment diagram of a frame structure

I have an exercise where I should calculate and draw a bending moment diagram for a frame structure. The frame structure is similar to the one below, image taken from http://structx.com: I would like ...
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### Does hitting an obstacle hard enough to break it actually reduce self harm?

Lets say that Car-A hits barrier that is fixed to immovable posts on either side of the road. The car's momentum is such that the barrier absorbs the impact and the car comes to a near instantaneous ...
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### Why does the max principle stress at yielding for a ductile material equal to its yield strength in a uniaxial tensile test?

It is thought that the maximum principal stress for a ductile material is equal to its yield strength, in a uniaxial tensile test. This is also shown in the attached picture. I want to ask why is this ...
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### Why tensile test specimen is enlarged at its ends?

The tensile test specimen used for tension test has an enlarged cross sectional area at the ends. The sources I'm referring to, suggest that this is the case so that the failure occurs in the central ...
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### Determine Bending Moment

Need help determining the bending moment acting on the column. At the top of the column, the cantilever tube is slid into a shorter piece of tubing. The shorter piece of tubing is welded to the ...
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### Why we needed to relate internal resistive forces with area (stress)?

When we load a body, say a prismatic bar, axially, internal resistive forces are developed within it to oppose the elongation or compression. What was the need of relating these internal resistive ...
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### Bar released from upright position rotates about a lower hinge before being caught by a steel cable, how to calculate the tension on the cable?

I wish to check the safety factor of a steel cable that I've designed to catch a heavy bar that rotates freely due to the gravitational force acting on it. From the upright position, I'm assuming that ...
32 views

### Do tensile and compressive forces have significance only in pairs?

In strength of materials, there are two types of axial forces which can act on a prismatic bar - Compressive and Tensile. Do they significance only in pairs?
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### Reaction forces on a three support continuous beam with two of them requiring compatibility equations. Superposition method done wrong!

I need to analyze a continuous beam of length L and three supports: A (at x=0), B (at x=L/2), and C (at x=L). An applied load P is applied at x=3L/4. Now, at A, the continuous beam is bolted to a ...
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### Mechanics: example of less mass/volume gives more strength

Lets assume we have a mechanical element from uniform material that is supposed to work in a static load conditions. Moreover lets assume there is no gravity or gravity is negligible. Are there any ...
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### How are these bricks being supported?

My question is how can all of these bricks be supported by the thin columns on either side? How can there be that much empty space under all of the bricks that the arrow is going through? Looking at ...
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### What's the minimum number of required wooden pieces to make this door structually solid?

This is the basic requirement of the wooden door frame: The requirement is to make sure that the door frame does not skew or deform. Questions: What's the minimum number of wooden pieces to be added ...
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### A question on resonance

This is to settle a debate. I was working on a scaffold next to a building, as the wind blew, the scaffolding would sway. As I stood there I was trying to maintain my stability, but my movements ...
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### Calculating break point (bend) of a material

I'm trying to compare a really tough polyurethane to baltic birch plywood to see if I can use it instead (a lot of subtractive processes to the plywood, want to eliminate it) So what i'm looking for ...
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### 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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### Computing forces and moments acting on the sides of a rectangular shell element from corner forces and moments

I have a FEM program for shell elements implemented through the direct stiffness method. Using this program corner displacements of shell elements due to external loading are obtained through the ...
66 views

### Compute deformation response history from ground motion

I'm reading a book of Anil. K. CHOPRA related to Structural Dynamics, I'm intending to obtain the deformation response spectrum from given ground motion. What I have here in hand is ug(t) ground ...
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### How can I compute minimum thickness for a rigid acrylic panel?

If I have an acrylic (plexiglass) panel, how can I compute how thick it must be to resist bending. So, for example, if I have a sheet that is 24" x 36" and supported by the edges only (such ...
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### 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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### Which yield strength should I use in FEA in ANSYS; Engineering or True?

Attached is a figure to illustrate the difference in the value of yield strength as observed from the true stress/strain curve and engineering stress/strain curve. While conducting FEA in ANSYS for a ...
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### How to export 'simplified' geometry from Simulation workspace in Fusion 360 to ANSYS Mechanical?

I would like to export the defeatured version of my design to ANSYS. I tried adopting the following methods but they weren't working out. (https://forums.autodesk.com/t5/fusion-360-design-validate/...
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### Boundary condition at supported end of a rod

I have one end of a rod held in a hole of a 'rigid' part with no clearance, while the other end is loaded with a force. I have shown 3 simple reaction-force models in the picture. If my intent is to ...
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### Calculating the von mises stress in a 3D beam when given stresses and moments on both ends

I want to calculate the von mises stress in a given structural member. I want to generate a von-mises plot from this data. The forces are according to the local coordinate system of the beam. Also, I ...
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### Torsion of continuous vs simply supported beam [closed]

Say that I have a 2 span of continuous beam subjected to torsion, is the torsion value smaller than those 2 single span beam subjected to torsion of same value ?? I think the torsion of continuous ...
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### Thrust force on wind turbine

Could someone explain me how thrust force produces a bending moment on top of the wind power plant's tower?
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### Do all structures deform if put a load on them?

Suppose I have a concrete wall in front of me and I push on it, now it seems that I do work and the energy has magically disappeared. I am trying to figure out how this works, the explanation I ...
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### What Causes Asymmetrical Buckling in this structure?

I've been playing around with structural modelling on the SkyCiv platform and have created this structure, related to a project I am working on to educate myself. It is 2m wide, 3m long and 1.5m high ...
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### Constructing a structure with given constraints

I have a problem where I have a few points in 3D space with given constraints (forces, moments) and I have to create one connected structure which satisfies these constraints. Are there any pre-...
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### Increasing torsional-stress resistance of an Auger at its motor-shaft joint

An auger is used to move plastic balls and is rotated by a stepper motor. Due to the balls getting jammed sometimes, this induces stress on the auger at the motor-shaft junction and breaks. Images ...
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### PE exam: situations in which two question choices are close to my final answer: how to pick one?

Consider this question: I solve this eventual question and my answer is 7.29667: Among the question choices are 7 x 7 ft and <...
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### Computing the stress field of a structure made of 4-nodes shell elements (accounting for membrane action, bending and shear)

I am trying to implement my own FE code for shell structures. Most literature provide formulations and strategies on how to compute shell element stiffness matrix. I can already compute deformations ...
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### How do I start determining the forces in the 3 bars?

For part A I have $\Delta$A + $\Delta$B = $\delta$. For part B I've tried summing forces at the joints but keep getting lost. Any help is appreciated my final is on Friday.
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### Frame element stiffness with non-axis-aligned anisotropic area moment of inertia?

I've found equations for the $12\times12$ symmetric stiffness matrix for an element of a frame (a truss with welded joints): http://what-when-how.com/the-finite-element-method/fem-for-frames-finite-...
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### Fixed end moments

If B is a roller or pinned, should the fixed end moment for AB be (wl2)/8?