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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Pin joint system displacement question
A pinned system comprising bars of the same material and cross-sectional area is subjected to a vertical load P.
I am required to form a relationship between FAB and P.
The first part of the ...
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HOW TO DETERMINE SUITABLE JOINT CONNECTION TYPE? [on hold]
I understood about beam end release and how to do it in staad pro but i couldnot understand how to determine which type of joint connection is better.Is there any rule or criteria to know what kind ...
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+100
Can a speedbump safeguard a pipeline located below?
Recently I noticed a concrete speed bumper created near my parking. On enquiring the purpose, the committee who took the decision told me that the purpose of the bumper is to safeguard an existing ...
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1answer
25 views
How do I calculate the compressive strength of a wall?
I literally just have a thin steel wall that stands vertically with a load on top. The thin edges of the wall are oriented vertically with the load applied on top of the top thin edge, with the large ...
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1answer
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Is Belytschko beam defined for 3D or 2D?
from the paper in this link , which is the Belytscko beam. I could not figure out if it is a 3D beam or a 2D one.
if you don't have access to that paper, please check the page 73 on this link.
what ...
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1answer
39 views
How deep do you have to check for problems underneath a building site?
When you're putting up a new building, you have to check the soil underneath for stability. How deep do you typically have to check? What's the extent of your "due diligence" when ensuring that a ...
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1answer
43 views
Aluminum tube vs steel
Our question is what size and alloy aluminum tube can be used to replace steel tube in a vertical load application. Our current spec is 1.5” OD STD steel tubing 7 feet long. We will use 6 poles ...
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2answers
68 views
Design a part to straighten moment and reduce torsion
I have a configuration with two bolts and a point of force application (see figure).
I understand that, if perfectly rigid, the two parts depicted in the figure will behave identically in how they ...
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1answer
35 views
Ball and Socket Wheel Concept
I am sure you all remember those prehistoric computer mouses that had a ball under it. I'm looking for any points and tips on how to create a ball and socket wheel that has an almost frictionless ...
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1answer
33 views
Self Weight in Moment Distribution (Hardy Cross)
When applying the moment distribution method also known as the Hardy Cross method, how do I take into account the self-weight of columns? In the case of the beams, I can just apply the weight load ...
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3answers
92 views
Structure analysis
I am currently designing a setup for an experiment which involves loading a weight to its extension arm, and by design this structure is not bolted to any surface so its free to move. I need to ...
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2answers
125 views
Can a crisscrossed metallic skeleton resist earthquakes for buildings?
To follow up with my previous question on the seismic design of buildings, I would like to ask if it makes sense to support buildings with strong thick 'crisscrossed' metallic frames.
I have the ...
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1answer
58 views
Analysis of Machine Frames With Cut Outs
I have a structure that is used to support two shafts which are carrying relatively high loads. It is composed of two columns and a "shaft supporting block" in the centre (almost acting as a beam). ...
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1answer
33 views
Dependency between load capacity for reinforced concrete slab and thickness
How does the load capacity for a reinforced concrete slab depend on the thickness of the slab?
Example:
Let's suppose that we have the following constants:
concrete quality (including the maximum ...
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2answers
37 views
Parallel Axis Theorem for x and y Shift
I have a quick question about the parallel axis theorem.
Let's say I have a box-like object rotated about the following pivot point
I was wondering, by applying the parallel axis theorem, would the ...
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3answers
52 views
Why not a reverse bending in the slab?
When I'm looking at images / videos about the load supported by reinforced concrete slabs, I always see a compression at the top of the slab in every point that varies from the center to the edges:
...
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1answer
86 views
Looking to design a cantilever support to hold up an 80kg projector
I need to make a support (preferably metal) for a projector to be fixed on the wall. The projector size is:
Width: 0.7m
Length: 1.1m
Weight: 80kg
If anyone knows how i can solve this please let me ...
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2answers
67 views
Can a horizontal foundation safeguard against earthquakes?
I have not taken any course in civil engineering. What I was taught was that a broad base would prevent something from toppling. So it makes me wondering instead of nailing the foundation of a ...
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1answer
28 views
Stopping Force of Irregularly Shaped Object
I have a quick question about the force needed to accelerate/decelerate an irregular object.
Lets say I have a 3D object with the following general shape,
This system is in general a gripper (gray) ...
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1answer
61 views
How to derive fixed-end moment of a beam?
Here is my attempt but I am not getting the right answer. Can someone tell me what I am doing wrong?
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48 views
Why is pure shear a “shear”?
If one looks up the meaning of shear strain, most sources talk about this situation:
That is, a force acts along a surface of an element at it is elongated, turning a rectangle into a rhombus. ...
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1answer
49 views
How is the stress concentration factor calculated in FEM?
I have written my own finite element code for a linear elastic (plane stress) problem consisting of a plate with a circular hole in the middle, fixed on one side, having a tensile force acting on the ...
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0answers
68 views
Machine Frame Design
How do I select the cross section for a machine frame? Do I need to refer to the AISC steel construction manual to find the capacity of beams, columns, etc?
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1answer
52 views
Engine Combustion Cylinder Wall Thickness
Been referencing this website for some time but now need to seek specific help. I am not an engineering student but rather a DIY hack who loves engineering and machining neither of which I am ...
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0answers
29 views
Constrained optimization using Lagrangian
I'm trying to optimize the weight of a truss with the constraint that the trusses don't face more stress than the material resistance.
Here is a sketch of my truss:
I have a Python function that ...
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0answers
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Structural analysis + thermal expansion using ANSYS static module
I am attempting to model a steel sample subjected to combined mechanical and thermal loading. The thermal loading can be quite elevated, where reduction in the elastic modulus will occur.
Does anyone ...
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3answers
86 views
How do I calculate the member forces of a truss when external force acts on the member (not joint)?
Given a three member truss structure shown here:
How do I find the vertical and horizontal displacements at M?
Assume all members are elastic and E,A, I and constant.
I start with finding the ...
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0answers
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Etabs Semi Rigid Diaphragms
In Etabs, if I model a building with semi-rigid diaphragms assigned to the floors, the floors will now transfer gravity loads when default meshing is assigned (as compared to rigid diaphragms ...
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1answer
23 views
Selection of Aluminum (or steel) tubing dimension based on uniform load on supported beam
I am installing shades on a section of deck. The shade will be made of sections of fabric (which will let some wind through), but I assume a solid section.
Dimensions are 3.5ft*4ft = 14ft^2 = 1.3m^2
...
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1answer
28 views
2D Solid - Axisimmetric - Missing properties and material
Goodmorning,
I'm trying to understand how 2D solid elements work. I want to study the local buckling of a simple aluminium pipe with thin walls.
From what I understood, I can use 2D solid elements ...
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1answer
77 views
Maximum tensile and compressive stress in a T-beam
Where does the T-beam come from? There's just a straight beam resting on two supports. And where do 10 and 80 come from? I am so confused.
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1answer
50 views
Determining the direction of internal forces in a truss
I am learning the method of joints, but there's no explanation on how to figure out the direction of internal forces in my course.
How do you know that BA is tension and BC is compression?
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0answers
44 views
How to state the PSD value (random vibration)
In random vibration analysis, the load is given as a PSD (power spectral density). The values are often $G^2/Hz$, but I have an example where the PSD is a pressure $Pa^2/Hz$. The value is written as $(...
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1answer
38 views
FEA: What is the difference between a spider of RBE2s and multiple SPCs
I am not sure what the difference is between using a spider of RBE2s. and multiple SPCs across a face. I've heard that the spider is the more accurate method as multiple SPCs make the model overly ...
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1answer
60 views
How to find the diameter of bolts in a flanged joint?
So I'm given this question with the following diagram:
Two sections of a pipe are joined in a flanged joint as shown in the Figure below. The difference in pressure from interior to exterior is 2 MPa....
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2answers
51 views
What equation are we using to describe forces in FEA?
Engineers often use Finite Element Analysis software to solve for stresses inside complicated structures to generate pictures like the one above.
I am familiar with FEA as a method to solve ...
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3answers
108 views
What are the possible implications of the heating of the structural stonework of Notre-Dame cathedral during the fire?
Yesterday, Notre Dame cathedral caught fire. The roof and the central spire were destroyed and some of the stonework was subjected to high temperatures for an extended period.
What are the likely ...
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1answer
58 views
How to compute core stress in honeycomb structure?
Assume I have a honecomb(sandwich) panel under distributed normal load. Each edge of this panel is simply supported(pinned) as on the picture below:
The problem is how to find the core stresses σ-z (...
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2answers
60 views
Influence of a diagonal fold on a web + double fold situation
I need to build a steel frame with a steel web in it, as illustrated below.
Flanges of the frame will be welded, as well as the web, along its whole perimeter.
Would adding a diagonal fold to the web ...
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0answers
31 views
Determination of Warping Function for Thin-walled Multi-cellular Beams
I am trying to find warping function $\mathcal{T}$ for a thin-walled multi-cellular beam. There are four rectangular cells. The governing differential equation for $\mathcal{T}$ is Eq. 8.98 as shown ...
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Traction Force or Reaction Force
I am doing an FEA of a link plate of a chain drive system. the plate is subjected to traction force at one pin joint this particular link is in contact with the sprocket. it is also in contact with ...
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1answer
57 views
Why/how normal shear stress is zero in thin-walled beams?
Please explain how the normal shear stress (shear stress normal to the cuve, C, defining the cross-section of a thin-walled beam) is zero. I have attached a screenshot from a book which says that the ...
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2answers
102 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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0answers
26 views
Can I use fixed support for a frame?
Can we use fixed support at columns in a frame?
Because If we do so , there will be 2 moments when we will cut the section.
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0answers
41 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
71 views
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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4answers
195 views
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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0answers
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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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2answers
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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
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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 ...
