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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What is the amount of force that will cause failure?
What is the amount of force required to cause the beam to deflect, shear or otherwise fail?
The force would be generated by a hydraulic piston. Let's
call those units PSI. The piston will be mounted ...
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1answer
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Does having a basement level increase overall earthquake resistance of a high rise building?
Does having a basement level increase overall earthquake resistance of a high rise building? Does it also lessen the burden on pile foundations?
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Stress Concentration: Hole in infinite thin plate loaded in biaxial tension vs biaxial compression
Is there a difference in the stress concentration of a hole in an infinite thin plate loaded in biaxial tension vs biaxial compression?
I ask because in numerous books (one of them in the screenshot ...
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Should I use ST or LT values for extruded rod?
In MMPDS for AA7075-73511 (extruded rod) the Table 3.7.10.0(g3) show both ST and LT values for transverse directions. For a rod with circular cross section there is really no Short and Long transverse ...
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Other than yielding, what type of stress you check for ASD?
ASIC 360-16, in page pdf 330, it says
"For any single element, there may be a number of different allowable stresses that must be checked."
I can think of yielding. What else?
Rupture for ...
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In what cases we use both LRFD and ASD approaches in structural analysis?
In what types of situations we use both LRFD and ASD for the same structure? I of course do not mean a single analysis using both at the same time by mixing them. I mean, two separate analysis, for ...
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36 views
Global stiffness matrix from element stiffness matrices for a thin rectangular plate (Kirchhoff plate)
I have the element stiffness matrix for a thin "kirchhoff" plate. The plate is 3 [m] x 5 [m] and is simply supported on all edges. It's thickness is 0,2 [m]. On the plate there acts a ...
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39 views
Question on the determinacy of frame structures
I have been working on a program to solve frame problems, and I have used the following formula for determining whether a frame is statically determinate:
$$RD=3m + r-3j-s,$$
where:
$m$ is the number ...
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Abaqus: How to properly retain nodes positions for models that undergoes two separate analysis (undamaged & damaged structures)
I'm not sure If I've worded the title correctly, but basically I have two steel bars, one that is undamaged (fully intact, model U), and another one is damaged (drilled a half pass through hole on the ...
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1answer
46 views
Single shear bolt shear force and moment diagrams
I’m trying to determine what the shear and moment diagrams of a bolt in single shear look like. Before anyone says it, I know that it’s rare that a bolt will ever fail first in bending, and this is ...
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2answers
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Unable to obtain closed system of equations using method of joints
I am currently working on some code to solve 2-dimensional truss and frame problems, and I have come into an issue with one of the problems. I need to come up with a system of linear equations that I ...
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1answer
66 views
Analysis Of Braced Frame By Hand Calculation
Suppose we have a rigid jointed, statically indeterminate frame with bracing as shown below:
Note: there would also be a distributed lateral load along at least one side of the structure and all ...
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1answer
41 views
What is the meaning of “load case consistent” in stress analysis terms?
I’m a (junior) stress engineer and have been tasked with sizing a lug. Various loadcases have been run through FEM and loads have been distributed into the lug bolt for each. In other words, each ...
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2answers
55 views
What is the significance of hinge in the internal structure of the beam?
I had come across a question on shear force and bending moment diagram where a cantilever beam with a roller support at point C is given and the portion beyond point C in overhang. Does this hinge act ...
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2answers
43 views
How do fiber optic sensors detect strains in a structure?
I am working on a project on detecting damage in structures using fiber optic sensors. I read the paper Structural Health Monitoring in Composite Structures by Fiber-Optic Sensors and found out that ...
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1answer
36 views
Stress Analysis University Report Help
I'm working on a final report for the mechanics of material course, and the project was to choose a structure or mechanical element and carry out stress analysis using solidworks and then confirm ...
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1answer
34 views
Degree of Freedoms in a Node of a 3D Frame/Beam Element
I recently took a quiz for my Matrix Methods of Structural Analysis Class, in which I encountered the following MCQ. My answer of '6' was justified, in my opinion, by the size of the stiffness matrix ...
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1answer
28 views
Solving for stiffness matrix numerically by a set of measurements
Is it in general possible when you have a mechanical structure (in this case I am referring to the structure in this post) and you want to determine the global stiffness matrix of this structure, to ...
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1answer
47 views
Missing items in geotechnical reports [closed]
In your experience, what items that should be in geotechnical reports are sometimes missing, and what do you do in that case, can you provide example? Do we look at codes or make best guess and based ...
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1answer
40 views
Structural design approaches ASD or LRFD
I have several questions regarding terminology as I get confused reading different sources.
What I learned so far:
ASD is also called WSD (working stress design)
LRFD is also called Limit State ...
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2answers
36 views
Representing slabs in FEM
When making structural analysis with FEM, do we normally use plate or shell elements to represent slabs? I checked and did some reading for the difference between shell and plate elements in FEM in ...
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1answer
47 views
Bending behavior of built-up C-Channel
I am analyzing a built-up C-channel for bending purposes (2 point loads of 1200 N each @ 30 cm symmetrically from the CL). The flanges are made of a different material than the web, they are also of a ...
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1answer
32 views
Wind load vs Earthquake load and R factor
I read somewhere that if for instance for a building earthquake forces are expected to be much higher than wind loads, we can increase the R (response modification factor) value, so that we bring down ...
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2answers
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Cybertruck Monocoque body design
For those of you who are following the development of the Cybertruck, the latest modification is a size reduction of the body by 3%. Assuming this is dimensionally and not by volume, do you think this ...
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2answers
38 views
Which would be the most rigid?
I'm trying to resolve a theoretical problem.
If I have 2 steel boxes made from the same gauge steel (3mm stainless steel) & one is 7 meters by 2 meters by 2 meters & the other is say 30% ...
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1answer
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What is the difference between base shear and pseudo lateral load in seismic analysis of buildings?
What is the difference between base shear and pseudo lateral load in seismic analysis of buildings or are they the same?
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How to make the earthquake response spectrum graph
As far as I understand, there are two ways to make the earthquake response spectrum graph. One by experiment with a set of oscillators with different periods, to which we apply the earthquake's time ...
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1answer
44 views
Plastic hinge locations in pushover analysis
In pushover analysis, why do we force the plastic hinge locations, such as indicating in our model instead of waiting for them to occur naturally?
Also, do we usually need to show the spread of ...
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1answer
33 views
names of some earthquake analysis methods
For structure earthquake analysis methods, do these all below mean the same thing, just ways of calling it differently?
Linear Response History Analysis
Linear Elastic Time History Analysis
Linear ...
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1answer
32 views
Modal Response Spectrum analysis
Is "Modal Response Spectrum Analysis" the same as response spectrum analysis? How about modal superposition analysis? This is the same or different? Or all are same?
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2answers
29 views
Earthquake time history analysis
Time history analysis of earthquakes for structures, is a NON-LINEAR dynamic method correct?
Then why is there also something called "LINEAR response history analysis"? What is the difference of this ...
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33 views
Provide stability for a 3D object with a support structure
This is a follow-up to this question. I wonder if structural engineering tools like Finite Element etc. might help create such support structures. If so, how?
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1answer
24 views
How is response spectrum result used for earthquake analysis
For simpler buildings we can use response spectrum analysis. How is this used? The maximum acceleration we get from this , is simply multiplied by the mass of the building to get F=ma , total ...
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1answer
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In structural analysis, does inelastic analyis mean the same thing as non linear analysis?
In structural analysis, does inelastic analyis mean EXACTLY the same thing as non linear analysis?
If not what is the difference?
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What arrangement of web members is better? [duplicate]
I have a problem regarding following two structures.
First one:
Second one:
What arrangemet is better ? Why ?
Actually I have no idea which one is better.
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How does virtual work method relate to matrix method or FEM in structural analysis?
I understand the relationship of force method and displacement method and how we use them in matrices in FEM.
How about virtual work? Is it used in matrices and FEM too?
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1answer
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Analysis Of Statically Indeterminate Structures By Hand
When double-checking/confirming results produced by structural analysis software, many engineers recommend verifying and spot-checking key or critical members if the entire structure is not analysed.
...
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1answer
53 views
Which method is better to solve indeterminate trusses, force or displacement method?
For statically indeterminate trusses, which method is better? Force or displacement method? And why?
I read somewhere that displacement method is not suitable for trusses but I must verify.
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1answer
23 views
Is shock spectrum always obtained for an undamped single degree of freedom system?
I am reading a textbook on fundamentals of vibrations and it has a very brief introduction to shock spectra. It mentions that
For comparison purposes, it is customary to use the response of an
...
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1answer
60 views
Structural Analysis of a TV Mount
I have a simple wall mount I want to analyze using hand calculations (pure beam bending if possible) that looks like this:
I want to be able to model it as if it was in a state of pure bending with a ...
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4answers
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What is the maximum angle of a shelf angled brace?
So suppose I want to make a single shelf protruding from a wall and to place a heavy object on it (Figure 1). A shelf like this would fail (assuming no internal mounting that penetrates into the wall)....
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1answer
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column yielding under earthquake
In the buildings designed with strong column weak beam concept, the columns will remain elastic, their plastic deformation will be limited. but this is not true at the base of the building. i mean i ...
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2answers
51 views
Bending moment in Euler-Bernoulli finite Element
I'm trying to calculate the bending moment distribution on a fixed-fixed Euler-Bernoulli beam. It is known that interelement nodes show different values for the bending moment. What is customary to do ...
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1answer
57 views
Is it safe to slightly cut the edge of RCC column for passage of pipe in bathroom?
The RCC column was cut in my absence due to passage of pipe for bathroom fittings. The thickness is about 1.5 in. Will it hamper the stability of structure?
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In Nastran, how to ignore fatal error due to failed convergence and move on to next subcase?
At the moment the whole analysis stops when 1 subcase fails to converge. How can I keep the analysis going such that all subcases are are run, even if they all might produce an error?
I'm pretty sure ...
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0answers
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In a nonlinear static two-step subcase, why does the load step decrease after the first step?
I am using MSC Nastran for nonlinear static analysis (sol 400).
Step 1 contains a small perturbation load laterally on a thin-walled cylinder.
Step 2 contains a very large compressive load.
...
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1answer
30 views
Elastic waves in very thin plate
Elastic waves in structural elements are described by
\begin{align}
\rho \frac{\partial^2 u}{\partial t^2} &= (2 \mu + \lambda) \frac{\partial^2 u}{\partial x^2} + \mu \left( \frac{\partial^2 ...
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1answer
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For arc-length method in nastran, how to analyse post-buckling behaviour with load decrease
I am currently trying to model the buckling behaviour of a cylinder using sol 400 nonlinear static analysis using Nastran. I am using the arc-length (modified Riks) method as apparently it can ...
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1answer
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Understanding Bending and Twisting Moments in a Plate
I am trying to understand Kirchoff Plate Theory and I am unable to understand the difference between bending and twisting moment for a plate. In a beam structure, if moment is along the axis of the ...
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1answer
173 views
Free pre-processor for Nastran?
I want to do a non-linear analysis (possibly SOL 400) on Nastran. I used PyNastran (python module) to set-up the BDF file for a Linear buckling analysis (sol 105). However I feel like it might be too ...
