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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Why are engine blocks so robust apart from containing high pressure?

Lately, I've been pondering why some engine blocks are so bulky, I always thought intuitively it was because they had to last a long time whilst containing thousands of combustion cycles but the more, ...
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General solution for the most critical pattern of live loading

From ASCE 7-05 code: ASCE 7-05 Section 4.6 states "The full intensity of the appropriately reduced live load applied only to a portion of a structure or member shall be accounted for if it ...
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Interpretation of shear flow/shear center of L-profile

I have calculated the shear flows and center of an L shaped profile. I assume they are correctly calculated (I followed the same steps as during the lectures for an I shaped profile). However, I have ...
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Vertical wave action on bridge

Rio de Janeiro, Brazil is currently stunned by the fact that yesterday a span of a brand new (innaugurated in January) bicycle bridge along the coast collapsed when struck by a wave, killing some ...
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Can I reduce the column moment due to beam, by setting the beam end to pin?

I have a structure, which contains only frame elements ( beam and column). From what I know, if I apply point load at the columns on both left and right hand side,and if the beam-column joint is ...
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What does it mean when actual member reaction is 100% of allowed?

I received construction documents for an extensive residential remodel and looking at the engineering there's a glulam drop beam with a calculated member reaction that is 100% of allowed (3965 lbs @ 5 ...
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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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How do you check a weld for applied moment?

I have a single angle connected to a double angle via a 3/16" weld I know there is a factored, applied moment at that connection. I would like to ask how I can go about checking the capacity of this ...
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Principle of Virtual Work vs Castigliano's (Second) Theorem

I had a look online and into some literature however I did not seem to find a good comparison for the two different methods. They are both used for determining displacements and slopes (rotation by ...
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Is it useful to stuff my glasses with newspaper to protect them?

(I'm not sure if this question belongs to this stack exchange, but it seems appropriate to me) I have a very practical situation and our knowledge is lacking to be able to solve our debate. The ...
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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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Mathematical representation of hinge and pin connection

Following on from this answer, I am reading about the difference between hinge and pin connections here, and I don't quite understand about it. I think I would need to see the mathematical ...
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Why the design of continuous beam is always more economical than beam with supports?

Assuming that I have a beam that spans across a few supports. I can design the beam as a continuous beam (a beam that is loaded and has more than two supports), or individual beams that each encompass ...
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How should one model a structural model with both line elements and area elements?

I am modelling my structure using FEM, and my structure contains line elements (1D) such as beams and columns and area elements (2D) such as walls and columns. My question is that, how can I proceed ...
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How to derive Equivalent Static Load for irregular structure modeled with FEM?

Building codes such as the Uniform Building Code (UBC) or International Building Code (IBC) require the determination of Equivalent Static Lateral Forces in order to compute $P-\Delta$ effect and to ...
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Truss manufacturer drawings unclear

I am currently looking at a set of truss layouts produced by our truss manufacturing partner for a residential building project. I have reason to believe these layouts are generated using Alpine (...
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Fragmentation of a curved cantilever beam under compression

Suppose we have a curved beam of a rectangular cross-section $A$, Young's modulus $E$, and a constant radius of curvature $R$. We now expose the beam to a vertical point load of magnitude $P$ at its ...
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Should P-Δ effect be considered for struts of a braced excavation?

Building codes such as BS5950 provide clear guidelines on how to consider P-Δ effect due to sway of a vertically loaded portal frame or single storey building, causing additional moment in the columns....
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How to simulate a crack in a PCB? [closed]

I want to break this PCB with some know force of X newtons in the bottom left tip of the PCB. The problem is that in Static Dynamics I just get infinite deformation and in explicit dynamics I really ...
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Do scaled models reflect strength characteristics of full size

Lets say you want to build a bridge out of carbon fiber. This has never been never been done before, and it's super expensive stuff. So your goal is to use as little material as possible, but ...
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How to know which modes are excited by a given input in modal analysis?

Consider a simple structure such as a beam, plate, ... Assume that you know how to determine the different modes of vibration of the structure. You are given an external input, such as a force or ...
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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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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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Plastic modulus

Are there some general guidelines for approximating the plastic modulus of steel under tension so that a bilinear stress strain curve can be defined for Loading beyond the elastic region?
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How can we derived the equivalent Lumped Mass Model for irregular building and how to calculate the errors?

Intuitively, building can be represented as a lumped mass model ( the taller the merrier!): Assuming a building is a lumped mass cantilever column also makes the global stability checks easier ...
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Increasing torsional-stress resistance of an Auger at its motor-shaft joint

An auger is used to move plastic balls and is rotated by a stepper motor. Due to the balls getting jammed sometimes, this induces stress on the auger at the motor-shaft junction and breaks. Images ...
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What is the advantage of statically indeterminate structures?

Most of the real life structures are statically indeterminate. What is the benefit of designing a statically indeterminate structure instead of a statically determinate one? I don't mean only beams ...
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Why does a continuous beam have less deflection than a pair of simply supported beams?

Inspired by this question, and also this answer to a separate question. I have two beam models, one with two independent spans (a full hinge), another is a continuous beam over both spans (only ...
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What could be the reason for these sections not agreeing?

I have two results that don't seem to match up and I can't figure out why. I built a hollow square section (HSS) using two different structural analysis softwares (they both agreed). However, they ...
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Structural Analysis of a Space Frame

I have a seemingly simple structure and I need to perform a hand calculation to check that the stresses in the members are below the allowable values. In its simplest form, the structure is a ...
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Accidental Torsion and Equivalent Static Load for an irregular structure

Important note: I am writing a structural FEM software from scratch, so I won't able to use existing commercial FEM package. I would need to know how all the important quantities are calculated from ...
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Determining the microstructure of steel after welding in modern computer software

How can the microstructure of steel after welding be determined in modern computer software? I am aware that there are 'classic' methods of predicting microstructures like Schaeffler, DeLong or WRC ...
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Arranging members within a truss efficiently

A wide variety of trusses exist for bridges and roofs. There are many different permutations when it comes to arranging the internal truss members. Depending on the direction, a diagonal member may be ...
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3D construction [closed]

Can someone please tell you what to start with to construct a Kids Bike Trailer as 3D. It should select material and geometry. I think I should start sketching with forces (children's weight) and ...
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Biaxial Bending Sign convention

I did a couple of quick calcs to better understand the phenomenon of biaxial bending. One thing that is currently tripping me up is the sign convention. For example, if we have a rectangular beam as ...
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Shear force expression for singly supported triangular load

From equilibrium: $$C_y = \frac{w_0L}{2}$$ And the load is given by: $$w(x) = \frac{w_0}{L}x$$ Thus the expressions for shear and moment are given by: $$V(x) =\int{-w(x)dx}=-\frac{w_0}{2L}x^2 + C_1\...
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How to determine fixed end moment in beam?

Why the Fixed End Moment (FEM) for BC is 3PL / 16? It's clear in the first figure that that when one end is fixed, while the another end is pinned, then the fixed end moment is 3PL /16 ... But for ...
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Is pin column-beam joint always have less moment, more deflection compared to fixed joint?

I am referring to the answer here: It seems that on a simple structure (The diagrams on the left the images below have fully-fixed connections, while on the right the columns are pinned connections ...
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How to calculate the relative contribution of each mode in seismic dynamic mode analysis?

In structural dynamic mode analysis, one would have to carry out modal analysis in order to get different modes that contribute to the response of the seismic ( or wind) force. Here is a nice summary. ...
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Can secondary beams be supported to columns occaisionally?

If there are secondary beams running between primary beams, and columns support the primary beams, then is it allowable to have the occasional secondary beam pinned to a column? Otherwise it seems to ...
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How to calculate principal moment of inertia of an unequal angle?

Is there a formula to calculate the moment of inertia of an unequal angle? I am not talking about x or y direction but the maximum and minimum moment of inertia about its rotated axes (usually ...
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1answer
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can a new foundation be dug alongside an existing house with a deep foundation without compromising the structural integrity of the existing house?

Can a new foundation be dug alongside an existing house with a deep foundation or cellar without compromising the structural integrity of the existing house? Subquestion: should I leave rebar or sth ...
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What are the principles (if there are any) behind the conservation of bending moment in frame analysis?

I notice from this question that the moments at joint connection are somehow "conserved", or being "transferred" from one element to the others. In other words, there are no "missing moment". Note ...
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Is it possible to convert uniform loads to point loads?

I want to perform a structural analysis on a portal frame using a finite element solver to get a displacements and reactions for a load. The software library only accepts loads applied to node, not to ...
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Is there any need to consider loading sequence in construction stage for structure analysis?

Load sequence in phases can be considered applying the self-weight load only to the story added in the appropriate phase. Assuming that the material will not go into yield stage ( will always be at ...
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Building Uplift due to water pressure

I have a building that is 7 story height (which 5 stories are basement floors which means they are underground) My water level is at 1.5 m from the surface. the stories have typical rectangular shape ...
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Minimum thicknesses of an elliptical cylinder pressure vessel

For pressure vessels in the shape of circular cylinders, we can use $\sigma_{hoop}=\frac{pr}{t}$ to find the minimum skin thickness by setting the hoop stress the maximum allowed value, and then ...
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Beams in Bending: Bending stress / strain distrution

first post so bear with me please! Studying Mech Eng and in all notes provided and I have come across online the stress/strain distribution is shown as I have sketched belo (see pic). Surely this is ...
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Steel Roof Truss Shape Question

On a recent project for a outdoor shed the roof support structure did not look like one of the conventional roof truss designs I have encountered. See snapshot below. (The span is 10 m with the ...
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Shear strength polymers

I was looking for some shear strength properties of common polymers/plastics.... I have not found any usefull information yet. I know polymers aren't that linear elastic, but I expected to find some ...

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