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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Overweight construction equipment for weight restricted plaza
We have to use our equipment on a elevated plaza that has a weight restriction of 2,400 lbs. per sq. ft. Each tire (4 total) carries a weight of 10,050 lbs. (1/4 of the gross weight of machine 40,200 ...
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Units of measurement for structural analysis
FEA engine
I'm using CCX finite elements analysis engine along with its pre- and post-processor CGX:
http://www.dhondt.de/index.html
https://github.com/calculix
Example
I'm looking at one example here ...
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How to determine the flexibility coefficent of this six member truss using the unit-load method?
I'm studying the Flexibility method described in the book "Matrix analysis of framed structures" by James M. Gere but I'm having a hard time understanding one of the examples. I'm stuck at ...
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Designing a footing to accommodate changing applied moment under ULS constraints
I am currently working on a system that will calculate the reaction distribution $p(x)$ across a footing with an applied load $P$ and applied moment $M$. There is one case that has me stumped: when ...
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Finding the bending moment diagram for an indeterminate continuous beam
In a recent lecture, we had the following example of an indeterminate continuous beam where we must find the redundant support reaction at $A$:
This was found by removing the support at $A$, and then ...
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Dlubal Rfem Seismic Analysis
I’m learning Dlubal Rfem recently and I have a problem about seismic analysis. When Equivalent Lateral Load is bigger than Modal base shear;for example on Sap2000 we scale modal base shear and we make ...
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Stress and Displacement of Cantilever Plate with a Uniform Load
Does any one happen to know of any resources that describe the stress and displacement of a uniformly distributed load in the direction perpendicular to the length direction of a plate analytically? I ...
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Calculating the required dimensions of horizontally-oriented weight-bearing beams
In the image is a design for a chemical etched piece of metal. Shown in white are holes formed in a sheet of metal, which is shown in grey. Highlighted in the red circle is one of four sections that ...
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How much force is acting on the screws I used?
Years ago I built a vertical rack to store long lengths of wood. The rack was built using 2x4" pine scrap. Imagine a typical wall assembly with a single top and bottom "plate" (2x4) ...
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Optimizing Simple Truss Member Angle
I am trying to optimize the angles alpha and theta, for which members of truss would carry the less loads. Given is location of force and value of force.
Problem is, that I get contradictory equations,...
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When should a bolt and hole be tapped at an angle, if ever, from a structural/strength standpoint?
Assuming the head of a bolt makes proper contact with its surface and clamps properly, and tapping an angled hole is not an issue, when would an angled bolt and hole (relative to the primary surface) ...
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Tension forces in a cable and reaction at the supports
I made this problem to better understand how supports react to tension forces.
Here we have a weight Mg attached to a cable, the left side of the cable is angled at 10 degrees, while the right side is ...
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What will the reaction forces of a support be in case of an angled cable
If a cable is attached to a support on each side, and there is a load acting on it somewhere along its length.
Is there going to be a vertical reaction force only if the the cable is angled?
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Why are stress intensity units MPa√m
The units of stress intensity are usually taken as MPa√m. Cracks are usually measured in (mm), could someone please explain why this convention is used an not consistent SI units
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Tensor of inertia of a curved beam
I need help calculating the inertia tensor for a curved beam.
I found the formulas for this in the article https://hal.archives-ouvertes.fr/hal-01084693/document[page 20, Appendix A] and decided to ...
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How to find Tensile Modulus of a layer of Plain Woven GFRP with GSM of Fabric given
I need to Input "E" the tensile modulus for analysis of a composite layer made from Plain Woven E-Glass Epoxy composite material.
I know the GSM (g/m^2) of fabric is 106.
Using GSM =106, ...
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Building Below-Grade Octagonal Room - Does this roof provide enough support for wet soil?
Building a small room below grade. Walls/Floor will be grouted stacked stone (apx. Rip-rap size, 2"-8" diameters). Roof design is intended to be set and grouted in on top of stone wall. Soil ...
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Advice on building an aquarium stand
I'm building a kitchen/bar in my unused basement area, and want to incorporate my 180 gallon saltwater aquarium into the design.
Before I decide on a design, I wanted to ask for advice/opinions on ...
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How to determine the resistance provided by cement mortar?
I am attaching a steel rail and post guardrail to the coping of an existing parapet. The actions produced by the guardrail on the coping incur at point A as shown below.
However, how do I find out if ...
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Calculate bending moment on cantilevered I beam
I am not an engineer, and the maths that I have seen on other forum posts is beyond me.
I am trying to calculate the load that can be supported by a cantilevered Ibeam.
The data is as follows:
Width: ...
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Energy dissipation from inelastic yield vs viscous damping
We divide the base shear of a structure during earthquake by R factor, to bring it down, to account for inelastic deformations. So let's say R factor of 4 means we divide base shear by 4 and design to ...
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Solving truss member forces graphically
Is there a way to solve truss member forces of a complex truss like fink roof truss where the {Edit: external} forces and reactions are known, the angles of all the members and the total base length?
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Structural Question Regarding Moving a Post
We have a post in our living/dining room that is inconveniently placed that we would like to move a few feet. One structural engineer briefly glanced at it and said that we could move it, but I am ...
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In Column Bucking strength of 24' 3"x3" Hollow Aluminum Tube with .125" Wall thickness
I am designing a Gin Pole to lift a 500# load. The pole will be hollow Aluminum tube 24'x3"x3" and .125" wall thickness pinned at both ends. The pole will be at a 45 degree with the ...
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Compound angle for support tri-beam / double knee brace
I'm trying to determine the most structurally sound way to construct a support beam for a serious treehouse. There are four options I've mocked up below - the first two are individual knee brace ...
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What is the most accurate mathematical model of a cantilever beam's bending?
I read there are multiple models for it,
Plate theory, euler-bernoulli, timoshenko beam theory etc
Which is the most accurate for modelling the bending of a stressed cantilever beam?
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FEA Help: Reference point in abaqus at mid length
I am trying to place a reference point (for interation and coupling) on the axis and the mid height of the cylinder. Please tell me if there is a better way then giving manual coordinates. Thank you.
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Analysis of a Beam under Non-static Case
I am interested in the distribution of the beam in nonstatic cases.
Typically we discuss the stress, and moment distribution when a beam is in a static case.
However, I am interested in this ...
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Elongation due to self weight - why the load acting on an element is gradually applied load?
Consider a bar of uniform circular cross-section. We are interested in knowing the elongation of this bar due to its self-weight. This is a common problem in an undergraduate course on Mechanics of ...
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Crack Width Calculation through Section Analysis for a Section Experiencing Nonlinear Stress Profile
Ultimately, my goal is to calculate crack width at the stem.
I made this SAP2000 hollow pier model with solid brick elements to analyze the stresses and tried to calculate crack width in AdSec with ...
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is a rebar arch structure a good idea?
I am thinking of building a simple shaded Arch for agriculture. I have an idea of building it with 30 ft sections of rebar that I will bend into a rough art shape. I would then weld rebar ...
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How are overhanging elements supported in buildings?
I wonder how overhanging elements, like those shown on images below, are made structurally sound. I assume that one can approximate the structure as a cantilever beam, which means that some parts of ...
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Does the weight of a pilot exponentially affect the necessary weight of human-powered aircraft?
The MIT Daedalus, a human-powered craft, weighed about 31 kg. This was significantly lighter than its pilot during its record setting trip, though I can't confirm the pilot's exact weight. Still, this ...
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What does$ Ast = N16 @ 175mm $centres means in designing reinforced concrete?
I have the following problem, which I already know the general steps into solving.
My general approach is: calculate I cracked as we are already told that the section is cracked, and then finally use ...
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Trying to Understand Solid Stress Output from SAP2000
I don't understand why solid stresses (s11, s22, s33, s12, s13, s23) are reported for EACH joint of a solid (an eight-node brick element). I suppose it is reported per solid, and the stresses ...
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Maximum static load on a wooden king post truss
I have a garage with a roof which has a wooden king post truss that spans 4m ( with a total of 14 trusses spaced 450-550mm apart). Roof pitch is 35deg, and beam dimensions are 38mmx90mm, soft wood I ...
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General formula for shear force and bending moment
How do you find the general equations for shear force and bending moment?
For example, in this question, UDL = $w = 5.4knm$ and $L = 8.6$:
How do you find the constants of unknown from integration?
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Why is there a negative sign in case of moments caused by longitudinal stresses?
I came across the following relations in the plate theory. I, however, don’t understand the reason for the negative signs in Mx and My. There is, however, no negative sign in Mxy. I am guessing, this ...
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Why supposedly stress can't be MEASURED unlike strain?
My friend texts me, what she heard in one of her lectures today:
"Do you know stress can't be measured. It is only the strain that can be measured directly from a strain gauge."
I have ...
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Aluminium tubing strength - size/thickness v length for supporting its own weight
I want to make a simple fruit picker for a tall fig tree. Most of the fruit is lost as it drops when ripe and explodes on impact with the ground below. That or the birds get to it before we do!
So ...
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Is ultimate tensile strength is constant for a material?
Is ultimate tensile strength is constant for a material? I have performed a tensile test of a frame tube and I made the dumbbell for tensile test.
The test specimen (A) has a thickness 2mm while test ...
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Prokon Paradiso Error
I am designing a simple structure using PROKON. The structure is a full 3D space frame. When I run the analysis I get an error called the Paradiso Error. This error only occurs when the structure is ...
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How to design the thickness and diameter of a cantilever beam in bending for both composites and metals?
The goal is to find the optimum values of the diameter and the thickness of the circular cross-section of a cantilevered beam in bending, with the lowest weight (cross-sectional area). The main ...
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Influence line question for calculating maximum bending moment
I have the following question:
I have no trouble drawing the influence line but I have problems with finding the magnitude. Can someone please explain how to get $\frac{8}{3}$? How should I use the ...
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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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Is there a way to get a more 'cubish' version of the bucky-ball structure?
I've read that the reason bucky-ball architecture hasn't taken off in spite of its strength advantage, is because circular profiles don't fit well into rectangular plots, and appliances and furniture ...
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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 ...
