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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Natural Frequency of a Shear Frame
Hi I've been stuck on a problem for one of my exam revisions, we were asked to identify the natural frequency of the following structures
I know that the equation for the stiffness is as follows
Left ...
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Mechanism and static determinacy
I was doing exam question and am confused as to how to determine if the structure is a mechanism or not.
Say that j = number of joints, r = total number of reactions, b = number of bars.
For both (a) ...
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Solving an indeterminate truss with static redundancy of 2 confusion
I have the following truss and I want to calculate the reactions using the flexibility method
Using this method means that I need to break this indeterminate system into a determinate system and two ...
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Justification of static equilibrium for a cut structure/frame
Axial deformations are ignored. This structure is under the specified force:
Is the internal shear force in column BC equal to that of column DE?
If we cut the structure at middle of BC and DE ...
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Transforming the Area of a Hollow Square Section filled with concrete into the equivalent area of just steel
I need to complete the 3D stiffness matrix of steel concrete composite columns under all kinds of stresses (axial and rotational as shown in the image below). So because the section is a Square Hollow ...
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Symmetry to determine the support reactions of a statically indeterminate frame
The following is an indeterminate frame consisting of two beams that are rigidly connected to each other at the corner support.
I want to find the support reactions.
As far as I can see, this is a ...
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Direction confusion for shear and moment when sectioning a beam
I have been practising the superposition method lately and I am confused in terms of drawing the directions when sectioning. Here is the problem:
Heres is the process of converting a indeterminate ...
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Max bending moment estimate
Context: I study aerodynamics and want to design and build an RC wing to put the theory I learned into practice. The essence of the theory I learned is: Given some mass of wing building material, how ...
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Calculations of Retaining Wall
If I have to find the maximum bending moment of this retaining wall, is the maximum bending moment located at the toe? If not, where is the location of the maximum bending? In order to find the ...
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Method of Joints confusion
Say we have the following truss, with $1$ kN load pointing upwards at node 5. The goal is the calculate all the reactions and the internal forces within the members using the method of joints.
I used ...
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How to know whether a vertical truss displacement is upwards or downwards (using virtual work)?
Say I want to determine the vertical displacement of the truss at Node B
How do I tell whether the vertical displacement is upwards or downwards just by looking the real forces? Where do I draw the ...
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Calculating the reactions and using method of joints
Determine the vertical displacement of joint C of the steel truss. The cross-sectional area of each member is A = 400 mm2 and Est = 200 GPa.
I think I know how to calculate the displacement using the ...
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Bending of a cantilever beam
How is the bending of a cantilever beam negative when, some of the statics methods say otherwise, assuming I am applying them correctly?
When I used the singularity functions method, I obtained a ...
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Boundary conditions for symmetrical problem of truss
What is the symmetrical problem for this truss, specifically the upper right part of it. What boundary conditions have to be added (i.e. supports).
What confused me was the specification for the upper ...
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Analysing a multispan determinate beam by separating it into spans
Say we have the following indeterminate beam:
We can make it determinate by adding a pin at B, and then adding back the bending moment at B which was destroyed by the pin:
My lecture handouts then ...
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Confusion with the definition of Principal Stress
The principal stress in the textbook that I'm following is defined as
The maximum or minimum normal stress that acts on an element.
This makes sense when I take a plane state of stress and I get one ...
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How to use Mohr's circle to find stresses on a slanted plane?
Here is my attempt to the problem:
Does this make sense? rotation clockwise 60* from horizontal to normal of the slanted plane , therefore $2 \times 60$ clockwise as well on Mohr's circle.
I am ...
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Understanding out of plane principal stresses
Consider that the state of stress at a point is given by an element taken at that point as shown,
The principal stresses in the x-y plane are given as,
$$\sigma_{1} = {\sigma_{x} + \sigma_{y} \over 2}...
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Orientation of Principal planes with respect to plane maximum shear
Consider that the state of plane stress at a point is given by the following element
We obtain principal planes and planes of maximum shear at different orientations of the plane, where the ...
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Help for non-engineer? Cantilevered load question
Wondering if I may ask for some help from my engineering friends. I am a hobbyist woodworker and am trying to figure out a strategy for something I'm making. The idea is a drop leaf style table that ...
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How to find the shear stress just below or just above some elevation?
Say the cross section carries a vertical shearing force of 40 kN. And say I want to find the value of the shear stress just below the section a-a.
I am very confused about which area $(A)$ to take ...
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Rigidity and bending moment
When a beam which is fixed at one end and free at the other, is acted upon by a load P, the beam bends and we get a bending moment at every cross section of the beam. This bending moment can be ...
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What's the best shape (solid of revolution) for a cantilever beam to carry a point load at the free end?
How should you change the diameter/radius (while keeping constant overall volume) of the cross-section along the length of a round cantilever beam so that you minimise deflection with concentrated ...
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What does negative shear stress mean $\tau \:=\:\frac{VQ}{It\:}$?
$\tau \:=\:\frac{VQ}{It\:}$
My confusion lies within $Q$ term. $Q = yA$ where $A$ is the cross-sectional area of the segment that is connected to the beam at the juncture where the shear flow is ...
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Stress concentrations around rivets in compression
The stress concetration factor for an unfilled hole is around 3, but it decreases when a rivet is present. What factor can we expect for a hole with a rivet in it in compression?
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Maximum deflection in the beam
Consider a simply supported beam, acted upon by a concentrated load P as shown
By applying the method of successive integration, i.e. by using the differential equation
$$EI \frac{d^2v}{dx^2} = M$$
...
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How do you calculate the maximum bending stress in a beam with different thickness along different parts on the beam?
Here is a practise question that I am working on. The beam has different thickness due to the supports in the middle. I would expect the maximum bending stress be away from the middle due to the ...
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Is it possible to convert a structure with a .stl file to a solid structure in Abaqus?
I have a .stl file of a structure and I want to use this file to do a simulation in Abaqus. I need my part to be solid but I don't have any .stp or .iges file of the sructure. So, I imported my .stl ...
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How exactly the beam is twisting?
Consider an I section beam shown below, which is unsymmetric about the x-y plane.
I apply a load P, at the centroid of this section. The textbook I follow, says that the member will twist apart from ...
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Design support of a base for a load bearing vertical struture
I'm designing an elevator system to haul a load of 250 lbs. Did some rough CAD modeling of the system.
I'm looking for some help on how to mount the strut rails (72") such that the structure can ...
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Why in a rectangular cross section beam the shear stresses are parallel to the height throughout the surface?
Consider a beam with a rectangular c/s subjected to some arbitrary loading. At any cross section the shear force is V. This shear force is the resultant of all the internal resistive forces which act ...
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Direction of Shear Stress on the periphery of a circular section beam
The Question is from shear stresses in beams
Consider a beam made of circular cross section, in which at any cross section the shear force is V.
The textbook I'm following states that -
When a beam ...
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Due to what reason are the beams getting elongated?
I was studying about shear stresses in beams, where one of the ways the textbook tried explaining intuitively the presence of shear stresses in beams was:
Source : Mechanics of Materials, R.C. ...
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Do we allow mass and moment of the footing itself, when calculating ground support and eccentricity of a footing?
Suppose we are designing a footing for the wall of a building. There are two checks that are crucial.
Ground support: suppose the ground is assessed as being suitable to load up to 80 kN/m2. Then a ...
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Proving the advantage of a composite beam
The textbook that I'm following for studying bending stresses in beams, states that - "Engineers purposely design beams in this manner (composite manner) in order to develop a more efficient ...
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Will my brick veneer wall sustain the additional load of natural thin veneer stone, wire mesh, and plaster placed on top?
I have a (full, not thin) brick veneer wall on the front of my house. It is tied into the plywood (covered with paper) via wall ties and screws. I am wondering if I can apply plaster and wire mesh as ...
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Beam of uniform strength
Generally, for a given loading condition, the bending moment in a beam varies throughout its length due to which the maximum normal/bending stress at every section is different. For a given allowable ...
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Beam rebar doesn't develop its length in column. Reinforced concrete analysis and design
In reinforced concrete design, there are some cases that engineers have to design beams which rebar doesn't develop its complete length or hook length according to codes. It is because of restrictions ...
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How does one conclude from this, that neutral axis passes through the centroid?
The book I'm following for Strength of materials states that, in a beam with symmetric cross section (about the plane of bending) and in pure bending, the moment of cross sectional area about the ...
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A problem on beams
Problem -
I have interpreted "by hinging them together at B" as following -
Now if this is the case, then applying a load on the right beam will have no effect, in my understanding, on ...
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Weight of the beam not considered in Macaulays method
I'm currently writing a lab report following an experiment to compare the Theory of Macaulays method to the lab results. My query is, None of the lectures or teaching I received has considered the ...
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How much load could the ceiling hold
I am replacing the ceiling in my flat with some soundproofing materials and since these are heavier than usual materials used I want to check if the new materials would pose a problem.
The room I want ...
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Why does Poisson's ratio always have the axial strain as the denominator?
Why can't we divide the lateral by the axial strain? Why does the axial strain always have to be the denominator? Would it matter if I was careless and accidently switched them around?
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How many more degrees of tilt can the Millennium Tower in San Francisco withstand before it becomes structurally unsound? [closed]
How many more degrees of tilt can the Millennium Tower in San Francisco withstand before it becomes structurally compromised/unsound?
"...An examination in 2016 showed the building had sunk 16 ...
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How can I find the right resonant frequency of a chassis?
Structures have infinite DOFs, so it possess infinite mode shapes. How can we find the right resonant frequency out of the infinite resonant frequencies so that we can save our structure?
For example, ...
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What is meant by Direct and indirect stress?
The book that I'm referring to for studying Strength of Materials states that:
"The loading case discussed here is an example of simple or direct
shear, since the shear is caused by the direct ...
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Contradicting Results of a Truss Structure
I saw this analysis online but I have noticed contradicting values from this method of analysis. The drawing of the simply supported beam comes from the crane structure above. All we desire is the ...
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Deformation of a plane in Torsion of a Circular Shaft
Consider a shaft which is fixed at one of the ends and is acted upon by a torque at the free end as shown.
We take a plane inside the shaft as shown in the figure before the torque is applied. I'm ...
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UDL vs Point Load on Truss
I have the above situation with a Warren truss and a UDL acting along the bottom of the truss. The UDL is $60 kN$ per $3.75$ metres. The distance between the joints along the bottom is $3.75$ m. I am ...
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Why is the unit load facing upwards? Flexibility/Force Method
I used the flexibility method to solve questions like this, so I know you have to have a primary and secondary structure. My primary structure looks like this:
So if I apply my virtual load, I got ...
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