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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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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1answer
137 views

How to compute core stress in honeycomb structure?

Assume I have a honecomb(sandwich) panel under distributed normal load. Each edge of this panel is simply supported(pinned) as on the picture below: The problem is how to find the core stresses σ-z (...
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0answers
103 views

Analysis method for two-way slab floor with central column

What method would be appropriate to analyze this concrete structure? A two-way rectangular concrete slab with walls and central column. I would like to understand how to model it with either yield ...
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1answer
54 views

Normalizing the compressive stress to a cylinder

I'm not an engineer but a neuroscientist. I do research in spinal cord injury whereby a clip is used to clamp the spinal cord to induce a bilateral compression injury model. My research looks at the ...
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2answers
2k views

Is it safe to slightly cut the edge of RCC beam for passage of AC Vent and wiring?

My electrician made a cut in the wall and the beam as in the image in my absence. The cutting is done with hammer and chisel and it is around 1.5inch deep..I'm really worried that it might impact the ...
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0answers
21 views

How quadrilateral elements represented in most FEA solvers for structural mechanics problems?

How quadrilateral elements represented in most FEA solvers for structural mechanics problems? I know that Nastran-95 represent quadrilaterals for membrane and bending elements as a set of triangles: ...
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4answers
77 views

Bending moment calculation

Considering all the variables are the same, how to rank these connections from highest to lowest bending moment?
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0answers
28 views

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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0answers
59 views

How to compare two acceleration sensors side-by-side?

I have a single axis analog capacitive acceleration sensor (from PCB Piezotronics) which is very reliable but expensive. Now I need more axis, unfortunately can not afford buying anymore. So I have ...
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0answers
31 views

Most efficient way for finding the rotation angles after moment distribution (Cross method)?

First of all, I have taken a look at the Grinter's method, which is similar to Cross, but balancing angles instead of moments. My question assumes that we are using the Cross method, and not the ...
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0answers
76 views

How to join two beams rigidly?

Hi I am making a beam model using Abaqus. There are two beams created. I wanted to join two beams rigidly in the connection to transfer moments between beams. However, I do not know what connector or ...
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0answers
3k views

How to calculate the required thickness of a steel stiffener plate in a corbel/bracket

I am dealing with a setup similar to the image below. The horizontal plate is bolted to a horizontal concrete surface (Bridge Abutment). And a horizontal force is being applied to the the vertical. ...
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0answers
193 views

How to integrate ∫vᵢ(uᵢ² + vᵢ²)dA in calculating monosymmetry index of an angle?

I saw this question asking about calculating monosymmetry index of an unequal angle. What I need is a formula to calculate $\int v_i{(u_i}^2 + {v_i}^2)\text{d}A$, given the depth $d$, breadth $b$ and ...
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0answers
51 views

Affect of Cast in Pipes in a 1m thick Raft Slab on shear

I am designing a 1m thick raft slab and the drainage guys have thrown in 100mm diameter cast in pipes all over the raft. See Attached images 1 & 2. Wondering how this will affect the shear in the ...
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0answers
610 views

how to release specific degree of freedom in ANSYS Workbench?

I'm designing a truss which has 9 elements in ANSYS Workbench. since it is a truss, all of the elements are truss elements and can not tolerate momentum. I used <...
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100 views

How to obtain relative movement and rotation of bridge bearings?

In structural analysis of a bridge using whatever software, such as MIDAS or SAP 2000, it is easy to obtain the deformation of individual nodes. However, for bearings, what we want is the relative ...
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0answers
34 views

Using seismic base isolators in light, flexible buildings

Using seismic base isolators dissipate a great deal of energy that would enter to a structure, but at the same time they increase the natural period of vibration of the structure. Now, if we had a ...
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0answers
24 views

Help sizing of lug attachment flange/plate?

Apologies for the crude drawing attached, but here goes. Given Fx, Fy, and Fz loads applied at the lug hole, I've distributed the loading into each of the 6 fasteners to size them. I've also sized the ...
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0answers
16 views

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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1answer
46 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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1answer
112 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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0answers
33 views

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
18 views

Finding reactions of a continuous beam

is it possible to find all the support reactions of this continuous beam using fourth order equation without using principle of superposition?
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0answers
87 views

Analysis Of Planar Frame Using Hardy Cross Method (Moment Distribution) With Sway

The image shown below is a sketch of the structure/frame that I am attempting to analyse using the Hardy Cross (Moment Distribution) Method. I need to find the bending moments, axial forces and shear ...
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0answers
520 views

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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0answers
34 views

Constrained optimization using Lagrangian

I'm trying to optimize the weight of a truss with the constraint that the trusses don't face more stress than the material resistance. Here is a sketch of my truss: I have a Python function that ...
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0answers
62 views

Etabs Semi Rigid Diaphragms

In Etabs, if I model a building with semi-rigid diaphragms assigned to the floors, the floors will now transfer gravity loads when default meshing is assigned (as compared to rigid diaphragms ...
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0answers
54 views

How to state the PSD value (random vibration)

In random vibration analysis, the load is given as a PSD (power spectral density). The values are often $G^2/Hz$, but I have an example where the PSD is a pressure $Pa^2/Hz$. The value is written as $(...
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3answers
199 views

Honeycomb structures vs shear stress

Honeycomb structures are made of top and bottom shells and honeycomb geometry at core. In terms of bending load, maximun normal strains take place on top and bottom hence, sheet parts can support them ...
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0answers
47 views

STEEL CONNECTIONS

Hi, so, would you consider the connection detailed here as fixed or pinned during your structural analysis?
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0answers
34 views

What does 'Analysis Model Value' in NASTRAN optimization mean?

I am new to MSC NASTRAN and PATRAN. I am running a simulation on composite laminate optimization. While creating the design variables for the study, I noticed that there is a parameter called '...
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0answers
67 views

Calculating the Structural Forces Required to Support a Robot on an Overhanging Beam

this is my first time posting on here and I have a question regarding the structural properties a beam will need in order to fulfill some requirements we have for our robotics team. The scenario is as ...
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0answers
373 views

Beam element stiffness matrix for variable area cross section with mass and shear center not coinciding

I would like to find the full (12 by 12) Timoshenko beam element stiffness matrix for a variable cross section with mass center axis and elastic center does not coincide. I have the full stiffness ...
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0answers
39 views

Check of a nominaly pinned steel joint

I am interested how to check a nominally pined joint. Especially how to check its rotational capacity and whether i can define it as nominally pinned in structural fem model. I understand that there ...
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0answers
266 views

Maximum slope of the road for a car pulling a trailer

I have a five meter long, 2.40 meter wide, 200 kg portable catamaran I've built at home. To transport, I bought a semi-finished trailer, just the running chassis; and built the upper structure, namely ...
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0answers
452 views

How can I use the bending stiffness of corrugated cardboard to determine maximum stacking heights of pallets loaded with glass bottles?

I am doing a project at the moment which involves improving the packaging operation at work. Right now I am looking at ways to improve packaging selection based on engineering principles, rather than ...
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0answers
222 views

What are the general consideration for tendon profile in a post tension slab?

How the tendon profile is calculated for banded-distributed disposition? In the following figure why is the tendons profile one in the top fiber and the second in the bottom fiber? If the location is ...
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0answers
559 views

What is the minimum diameter for vertical bars in a column according to ACI?

What is the minimum for vertical bars in a column according to ACI and I am looking for a particular condition where diameter must be greater than 0.625 in. (when using S-concrete for column design it ...
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0answers
24 views

Is it possible that a considerably thicker portion of slab would decrease the moment capacity of a raft slab

If I Design this slab as a flat 1500mm thick slab throughout ignoring the step will the design be conservative. I'm worried the extra stiffness created by the step, will attract the moment into the ...
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0answers
323 views

How would I model a load bearing brick wall supported on a beam in FEM

I have a continuous beam supported on columns. I need the brickwork above to act as load bearing wall for the next floor above. How would I model this in a FEM suite like SUMO (Prokon) ? In SUMO I ...
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0answers
22 views

Constant on multiply-connected boundaries for Saint-Venant torsion

I am trying to solve the Saint-Venant torsion problem with FEA. I have read some classic text and stuck in finding the constant value of stress function on multiple boundaries (i.e. closed section ...
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1answer
176 views

FBD of folding table leg

I've drawn an FBD of one leg of the table the picture. I've a feeling I'm missing something. Am I?
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0answers
20 views

Boundary Conditions of a Stepped Beam

I would like to ask about the boundary conditions to be considered in a stepped beam. For a cantilever beam wherein the one end is fixed while the other end is free to oscillate along the z-axis, we ...
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0answers
10 views

Anisotropic constants and progressive failure along-side ANSYS Mechanical model

I am modelling a CMC plate bolted to a superalloy plate in ANSYS Mechanical. I set up the orthropic material properties of the CMC from literature (x,y,z modulus and max stress), and I am using the ...
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1answer
40 views

Economical difference with high-pressure vessel design pressures for fixed volume

Suppose space is not an issue and I need a fixed volume of compressed air (for storage), say 1m³. Is it more economical to manufacture a thick-walled vessel but with a smaller volume or a thin-walled ...
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1answer
45 views

Boundary conditions for a cantilevered Timoshenko Beam

I am trying to find out the boundary conditions for above given Timoshenko beam. The boundary conditions that I have derived are $x_1 = 0$ $$ \overline{u}_2^L = 0 $$ $$ \phi_3^L = 0 $$ $x_1 = \...
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0answers
33 views

Craig Bampton Model Order Reduction on Ansys

I am in the process of modeling a component as a flexible body in Simscape Multibody environment (Simulink). I need to superimpose rigid body model with the deformation model. The deformation model is ...
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2answers
65 views

Best support for a granite table top?: Flat bar 316L Stainless Steel or equal box section or unequal box section

Project is outdoor granite topped table. Table legs are two isosceles trapezoids crossed together at 90 degrees, with the legs having an internal angle of 80 degrees, made from 100 x 100 x 4mm 316L ...
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1answer
13 views

how can i find Spectral Acceleration (Sa(T1; 5%))?

I want to do incremental dynamic analysis (IDA) for my project and for hunt and fill algorithm i need the 5% damped Spectral Acceleration at the structure’s first-mode period (Sa(T1; 5%)) . Can i find ...
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0answers
18 views

correcting mode shape for modal damping

I have mode shapes and eigen frequencies from FE simulation. I have modal matrix and eigen frequencies corresponding to each mode. The mode shape is mass normalized. I am required to correct each ...