Questions tagged [structural-engineering]
Questions related to the integrity, design requirements, or analysis of structures.
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Standing desk sway stabilization
I have a standing desk that sways when I'm typing and it is in the standing position. I've read numerous things online about this and can't find any actionable information for stabilizing the desk. It ...
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Moment of Inertia Problem
Im currently studying for the FE exam and I came across a problem from a FE practice test that I'm confused on. The specific question is on the parallel axis theorem of a trapezoid and the D value ...
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Design forces for a home built trailer structure (tiny home or camper)?
I am going to purchase a steel trailer frame, and then I want to build a camper on top of that. This will be full height teardrop which is likely wood framed but I am also considering aluminum framing....
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Weight bearing capacity of a terrace with a 10" concrete floor reinforced with steel bars?
I want to put a stone table on a first floor terrace, approx weight of table top is 175kgs, and the base would be about 100kgs. Table dimensions if relevant is 42inches diameter. The base of the ...
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Dual Axle Tiny House Trailer Build; Question About Structural Integrity of Trailer Design
I have questions about the fabrication of a tiny house trailer I am building. The questions are focused primarily whether I am adding enough cross supports.
My overarching design principle:
That of a ...
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Motivation behind contraints on virtual displacements
Consider a body with displacement $(u,v,w)$, where $w$ is assumed to satisfy $w=w(x,y)$ (that is, the vertical displacement does not vary along the $z$ axis).
Why exactly should the virtual ...
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Which design is most resistant to tipping against 90 degree downward force?
Have a question sort of related to question at (What calculation to find how much force before tipping over?) but with slight modifications.
Trying to weld some tubing together and onto a heavier base ...
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Questions on structural eng drawing for egress window
I am installing an egress window in my basement to make it a legal bedroom. I am going to be doing most of the work myself (outside of cutting the concrete) but doing it by the book (permits, ...
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Wood vs steel supports for small bridge
I'm interested in building a small access bridge across a creek on my farm. This bridge will be approximately 5m long and 3m wide and my tractor is about 4000 pounds. I read somewhere a long time ...
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Calculation of Drone Fuselage Natural Frequencies
I'm looking to do a frequency analysis of a fixed-wing drone. The goal is to calculate the first few natural frequencies of the fuselage to verify there is no resonance with the wing structural/...
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Are there load bearing walls under a Howe Truss system
My house has a Howe truss system. It spans 27 feet and then reduces to a span of 24 feet. Roughly half the length is 27 and the other half 24 feet. In the 27 foot section there is a wall (running ...
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Why do two simply supported beams stacked on top of each other deflect more than a single beam of twice the thickness?
If the thickness of each beam in the stacked configuration is 't', the thickness of the single beam is '2t'.
Explanations in terms of Euler Bernoulli beam theory, or any other explanation that is ...
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Why is stress the same even if I change the material?
I was performing a simple static structural analysis using Ansys to check the stress value for different materials. I have kept the below parameters constant:
Geometry
Force (in N)
Area on which the ...
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Is there an english equivalent of a "Polplan" in structural analysis?
During my civil engineering studies, I've come across the notion of a "Polplan", a method for determining the possible infinitesimally flexible configuration of a statically indeterminate ...
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I am having a gambrel roof added to my ranch
I am having a gambrel roof added to my 32 × 32 ranch. Upon taking the old roof off, it was noticed that all the wiring for the original first floor was from overhead.
So my contractor built a 6" (...
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How to find the displacement at each interface of a composite structure subjected to shear force?
Imagine a block made of 3 horizontal layers of 3 different materials (shear moduli S1, S2, S3) and fixed at the bottom surface.
If I apply a displacement 'x1' (or shear stress 'V1') to the top layer, ...
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Load distribution for a load centered over the length of the middle joist in a 3-joist system
I'm not an engineer, but I'm trying to understand the correct analysis for what seems like a pretty simple case.
I'd like to know what the effective load on the middle joist is.
...
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Cuboid pressured container - will the pressure reach the shear pressure of the material?
I'm having a go at designing a water electrolyser for producing hydrogen. I would like to store the hydrogen with minimal compression effort. Up until the past week I have been thinking about using a ...
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Why is there a lack of data and analysis of elastic range of PTFE (Teflon)?
I am looking for the proportionality limit and elastic limit of PTFE (Teflon).
There are several papers which reported the mechanical behavior of PTFE in tensile test. However, almost all of those ...
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Creep of the materials
Does creep exists for all materials at any stress at room temperature? I searched for this and could not find any answer other than creep isn't significant at low stresses and low temperatures. What I ...
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Steel to aluminum structural equivalent
I am trying to build an aluminum trailer on an airbag suspension. The plans are for a steel frame and we are looking to construct it out of aluminum to save weight due to towing limitations. Not sure ...
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Comparison between hand calculations of a continuous beam with FEA simulation (Solidworks)
I've seen many videos and books where statically determined beams' hand calculations are checked using FEA. But why is it that FEA results don't match the ones obtained using hand calculations (in ...
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A benchmark to check the validity of a finite element analysis
Is there any well-established benchmark to test the validity of a finite element analysis, i.e. FEA? For example, a 3D model with specific loading and boundary conditions. Along with the expected ...
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Making shipping containers with wood instead of steel, is my calculation sound and valid?
Please criticize my idea, thanks!
For making shipping containers easily reusable as structural components for modular buildings, and reducing their carbon footprint, we want to made their structure ...
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How to find out the strain distribution of a block in a simple compression test?
I am performing a displacement-controlled compression test on a square block, where the top of the block is attached to a fixed plate, and the bottom of the block is attached to a movable plate that ...
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8 x 12 wooden bridge over creek
I am installing wooden bridge over small creek for ATV and tractor size is 8 x 12. I'm using 6 x 6 post, total of 9 posts. 3 posts will be in center of creek. In summer time its usually fairly low or ...
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Will a rectifier based on air gap and flexible foil work?
The white line is a flexible conducting foil suspended on the metal wire. I think the external DC circuit will induce a charge on the flexible part and the other charges move to ground. The charged ...
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Fixed End Moment for a point load at edge span
Usually, i solved this kind problems by divide into 3 span, AB, BC, CD
Then, using Fixed End Moment and Cross Methode to find the Moment
But, i cant find Fixed End Moment for the point load at the ...
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Superposition of cylinder stress and normal stress
I need to calculate the principal stresses for the given cylinder with thick walls inside filled with gas shown on this picture:
I used the Lamé equations, namely:
$$\sigma_{x} = p\cdot\frac{r_{1}^2}{...
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rotate gear while no keeping it engaged with other gears
i am trying to build a toy where i need gear B to rotate when gear A rotates but when gear B rotate through a outforce gear A shouldnot rotate i hope that explains it well. (:
Both gears are on the ...
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Can I modify the roof trusses in my barn to raise the roof
We're trying to raise the roof on our 1.5 storey pole barn. We're intending on just replacing half the roof as shown below. each truss is supported by 4x6 columns (the long side of the 4x6 is bolted ...
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Does triboelectric generator made with powder and wire mesh work?
One of the greatest challenges for triboelectric generators is surface charge, which ultimately depends on surface area. Why don't we make one triboelectric layer a powdered form and a crazy forest of ...
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Predicting breaking force of beam per length based on one testing
I've made a plywood carbon sheet and tested its breaking force, for a 200mm long, 50mm wide, 16mm thick it was 100kg +-
I was wondering if it's enough to help me predict what will be the breaking ...
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Bowing of a small chip on a vacuum chuck (or, maximum deflection of a simply-supported circular plate)?
I apologize in advance for any mistakes in terminology or ambiguity in explaining the problem. I am conducting an experiment that uses the following setup and am trying to figure out how the system ...
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How to find the effort required to lift a hinged platform?
I have an aluminum platform that weighs 200#, it is hinged on the long side. I need to be able to fold it up into the vertical position when it's not needed. Before I get crazy with nitrogen charged ...
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Interaction Diagrams - Reinforce Concrete Design
I am confused on how to located the c value of an interaction diagram. I am given a unsymmetrical bar placement and there is a result that produces a negative moment meaning the location of the point ...
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Flexural strength of 1x1 aluminum
Trying to build a rather odd tool box that will sit on the bed side of my truck and sue to a swinging arm with a pneumatic shock assist will lower and swing it outward till it hits a rubber stopper ...
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EPS board with compressive strength declared 600kPa, can it withstand 6kg/cm2 without deforming
600 kPa is declared for boards of 600x1200 and the same for 1200x2400 (mm)
Does that mean that they have calculated this 600kPa for the material as such or is it a given per m²?
convert 600000 N/m² to ...
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rows of lights with steel rope (rigging wire) - 12 m between stainless pipe structure and concrete wall
Hello Engineering Stack Exchange.
I have been asked by a friend to hang some lights in a space beneath an arched bridge. The bridge is protected so no holes can be drilled into the arched stone; but ...
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What material performs best in this situation?
Take a long, thin rod, say .25 mm in diameter and 200 mm in length.
Filling these fixed dimensions, what kinds of materials could the rod be made of such that it minimizes how much the rod bends under ...
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Orange spots at hot dip galvanized surface
I like to ask you about orange spots after galvanizing of Steel Purlins. I attached some of the pictures. Please advice the solution with your expertise.
Thank youenter image description here
enter ...
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With respects to the North Channel (Irish Channel), has a causeway ever been proposed for a crossing?
Former UK Prime Minister, Boris Johnson raised the issue of a bridge between Scotland and Northern Ireland; his impromptu estimate of £15 billion was probably a little wide of the mark.
The issues are ...
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Bending moment capacity of T-cross-section (reinforced concrete)
I have a question regarding a simplification/derivation of the (ULS) bending moment capacity of a given T-cross-section, with compression-zone on the flanged side. The problem is that the rebar-strain ...
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Buckling of supported pillar
I am wondering how the "buckling number" of a timber column is altered by having a vertical element attached to it. Blue is the roof, green a concrete wall and black is the timber column and ...
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What are good insulators aside from glass?
The insulation properties of glass is apparently a factor in its popularity in modern construction.
Natural stone, by contrast, is a poor heat insulator.
What are some other building materials, i.e. ...
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Spectral Matching near fault sites (Time-History in ETABS)
While doing a Time-History analysis on ETABS and reading ASCE 7-16 I found that spectral matching is not recommended for near fault site erthquakes (<= 5km). In my case, and according to studies ...
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Infinite life of a material, Fatigue Strength
After 10^6 cycles a component is considered to have infinite life. What makes 10^6 cycles a deciding factor for infinite life? Why not 10^8?
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What does cycle mean in fatigue strength diagram?
A shaft at an usual factory might rotate 2000-3000 (10^3-10^4) per day. So, its rotation cycle easily reaches numbers indicated on X axis below. What does number of cycles in the diagram below exactly ...
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What is the equivalent rotational/angular stiffness of a beam
I'm trying to model a larger system and working through a conceptual issue. I'm familiar with the concept of expressing the stiffness of a beam as an equivalent spring stiffness like in the image ...
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Post and steel rope framework for grape vine
I am planning to build a framework to support a grape vine above a patio. Ideally I would like to use steel rope to provide this framework, rather than a full timber frame.
Diagram attached.
There is ...
