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# Applied Mechanics - Science topic

Explore the latest questions and answers in Applied Mechanics, and find Applied Mechanics experts.

Questions related to Applied Mechanics

This subject is important because evidence of conoidal rough cracks is observed experimentally on various macrographs of broken specimens, under fatigue for instance. Our recent works (see below in answers) provides associated physical quantities.

Greeting Researchers

It is well known that within the linear range, the in-plane and transverse motion of a plate are independent of each other i.e. the equations governing the in-plane and transverse motions are uncoupled. The stiffening/softening effect of the in-plane loads on the transverse vibrations of the plates is then accounted for by considering the work done by the in-plane loads during the transverse motion. In FEM, the work done by the in-plane loads is used to obtain the geometric stiffness matrix. The FEM equations can be given as

Ma + (K + Kg)u = f ... (1)

where u is the vector of nodal displacements, a is the vector of nodal accelerations, K is the stiffness matrix and Kg is the geometric stiffness matrix.

When the range of motion is no longer linear, the equations of motion for the in-plane and transverse motion are inherently coupled. In this case, incorporating geometric nonlinearity in the Von Karman sense, the FEM equations may be written as

Ma + (K + Knl)u = f ... (2)

where Knl is the nonlinear stiffness matrix.

Now my question is

**whether it is necessary to include Kg in eq. (2) i.e. whether the correct dynamic equation of motion with the incorporation of nonlinearity is as shown below in eq. (3)**Ma + (K + Kg + Knl)u = f ... (3)

My opinion is that since in the nonlinear case, the equations of motion are inherently coupled and thus, there is no need for the inclusion of matrix Kg as done in eq. (3). The coupling is incorporated through the matrix Knl and eq. (2) is the correct dynamic equation of motion. In the linear case, since the equations of motion are uncoupled, it is necessary to add the matrix Kg to incorporate the effect of the in-plane loads on the dynamics of the transverse motion.

I would like to have your valuable opinions on the same.

Thank you for your time.

Best Regards,

Jatin

I have written a numerical model for calculating the elastic deformation of two elastic bodies in 3D static contact. The code takes the applied laod, Young's Modulus, Poisson ratio, and surface profile of each body. Calculates influence coefficients based on the equation provided by Love [1]. The problem is solved by conjugate gradient descent and elastic deformation is calculated by Discrete Fourier Transform- Discrete Convolution method.

I tested the model on ball-on-flat and ball-on-ball geometries with the same material properties of each body. I am facing the problem that the elastic deformation contour is diagonal instead of concentric in these cases. The pressure distribution normalized at Hertz Contact pressure and contact width is correct, but the deformation is not. I have double-checked by Kernal/influence coefficient matrix but can not seem to understand this behavior. I have attached the 3D plots of the example (ball-on-ball), the 3D plot of the influence coefficient at 1 point, and the contour of calculated deformation.

Any help, guidance to solve, or help in understanding the problem would be greatly appreciated.

Thanks.

A.E.H. Love. Stress produced in a semi-innite solid by pressure on part of the boundary. Philosophical Transactions of the Royal Society of London, 377:54{59, 1929.

i am searching for new sensors that is used in cars for effective performance of motor.

can you give me a book or paper or introduce me a site?

Hello,

I have several structures which is composed of an upper body and an under body. I want to compare different upper body with each other (therefore several different structures) with Finite element software. I also want to lower the stiffness of these under body to have the same stiffness on the different models and thus be able to compare upper body between them. For this the solution is to vary the Young's Modulus of these different under body. The problem is that some are longer than others in terms of length. How to take this parameter into account?

Wake formation has been largely observed behind objects in real use e.g pillars, vehicles, buses, cars and building.

It has also been regions of large interest over decades.

So the question here is ? what are disadvantages of wake formation?

why they are so important?

Hello ResearchGate,

I'm simulating a blanking process in 2D using Abaqus Explicit with ALE. When the Johnson-Cook criterion is satisfied, elements start to be deleted, thus simulating the fracture at the end of the process. However, no matter how much I try to initially distort the mesh so that it gets more structured by the time fracture starts, the element deletion propagates "diagonally through the elements" (see attached screenshots), which leaves some of the not deleted elements connected by just one node (again, see attached screenshots). This stretches those elements to the point where my stable time increment gets pretty low, my burr is distorted and large, unrealistic stresses appear. I've tried to make the mesh finer, which hasn't really solved the problem. I've also tried to activate DELETE DISTORTED ELEMENTS, but this option doesn't seem to work, as the elements get stretched but their characteristic length remains large, as well as their area. I've tried applying the minimium dt option of this tool with no success (as the only parameter that seemed to be altered by these distorted elements was the stable dt).

This question:

**https://www.researchgate.net/post/How-can-I-solve-the-problem-of-excessive-element-distortion-in-2D-modelling-of-blanking-process-with-Abaqus-explicit**deals with the same problem but none of the answers given seem to help.I've attached a couple of screenshots that showcase the problem. If anyone knows a workaround or has any suggestion they will be very welcomed.

Have a nice day :)

Can an elliptic crack (small enough to remain a single entity, with

**no internal pressure or shear force**) inside an isotropic material (no boundary effect) be expanded in its own plane under**externally applied shearing stresses**only?If yes, how did you show that? Do we have experimental evidence for the process?

Greetings researchers!

I am using FEM to obtain the time response of the nonlinear forced vibration of plates. I am using plate elements based on Reddy's HSDT and Newmark time integration in conjunction with the Newton-Raphson iteration to obtain the time response.

It is well known that multiple steady-state solutions can exist in the case of nonlinear forced vibrations. Also, all steady-state solutions are not stable.

*In practice, unstable solutions are not realizable and the system assumes any one of the stable solutions depending on the initial conditions.*I was curious to know

*whether the FEM predicts only stable steady-state solutions. Or does it predict stable and unstable solutions and the stability of the predicted solutions needs to be determined through other means?*Thank you for your valuable time.

With best regards,

Jatin

Hallo every one,

I did nanoidentation experiment :

1 photoresist with 3 different layer thicknesses.

My results show that the photoresist is harder when it has thicker layer..

I can't find the reason in the literature.

Can any one please explaine me why is it like that??

is there any literature for this?

best regards

chiko

Hello.

I am trying to do a static analysis of a torque box using shell elements and I have the following issue.

I have modeled the Boeing 737 wing (torque box) in Autodesk Inventor using surfaces.

Then I transferred it in Ansys Workbench to start the FEA analysis.

However, I want the inner structure of the wing to be made using composite materials.

So, I opened an ACP module. In that module, I cannot hide some surfaces and here's where the problem is.

If I can't hide them, then I cannot select the ribs and apply an Oriented Selection Set.

I tried, also, making three different ACP modules and then assembling them in static structural (transferring shell data) however that results into an error.

I have attached my project file, without the ACP module.

The uniaxial (direct) tensile test is not commonly used for masonry structures. Researches mostly rely on bond wrench or bending tests for masonry structures. My questions are:

- What are the main reasons for the direct tensile test being used so little for masonry structures (the brittleness of the material? the low tensile strength? complexity in the boundary conditions, i.e. chances of introducing flexure in the specimen)?
- Are there additional complicating factors with performing direct tensile tests on specimens retrieved from existing structures? Let's say one is able to retrieve a vertical drill core from a masonry structure, what are the additional problems one faces with performing a direct tensile test on such a specimen (compared to a lab made couplet specimen)? Is it perhaps the loaded faces being not completely parallel to each other?

Regular polygons of trigonal and hexagonal symmetry are used as yield criteria in theory of plasticity:

References for regular icositetragon (24-gon) as yield criterion are sought for a systematization of yield and strength criteria.

The beam has a varying cross section. Also one of the sides is loaded uniformly by a force. See attached file for more clarification.

Hello Researchers,

Say that I have

**'p'**number of variables and**'m'**number of*constraint equations*between these variables. Therefore, I must have**'p - m'**independent variables, and the remaining variables can be related to the independent ones through the*constraint equations*. Is there any rationale for selecting these**'p - m'**independent variables from available**'p'**variables?I am trying to determine the maximum true contact pressure [Cylinder on flat body model]. I only have the Vickers hardness value (500 HV for 10 kgf load). Is there a way to correlate them?

i mean do some thing make abaqus understand that if i put a mass on a point in space , if that point move anywhere mass will also moves with it , that what i mean , if that can done by just put that mass in a datum point for example ??

if i defined mpc link between that point which i defined mass on it , is that mean that mpc link is work with point only and mass together ???

hello

I want to simulate a triboelectric nanogenerator by COMSOL MULTYIPHYSICS.

How to apply mechanical force for contact separation mode?

in tutorial files or articles just sweep the gap between the triboelectric layer for measuring Voc and don't use solid mechanics to apply mechanical force and when I use that facing an error: Failed to find a solution for the initial parameter.

is there any way for direct measurement of the output voltage of TENG in terms of applied forces by COMSOL MULTYIPHYSICS simulating?

I would like to know if the SUPG method has any advantages over the least squares finite element method?

Thank you for your reply.

Does a single-valued description exist for isotropic materials?

Hi all,

I am designing an electrosorption experiment using the 3 electrode system (Working electrode-WE, Counter-CE, and Reference-RE) , and I want to compare the results with OC adsorption. In order to perform an OC experiment, I just need to remove the CE from the potential-stat (still applying the voltage in my solution), am I correct?

Also, for electrosorption, can I apply magnetic stirring? If so what is a good rpm range for it? In cyclic voltammetry (CV) experiment, the electrolyte is kept unstirred to make sure mass transport can occur only by diffusion due to concentration gradients created around the electrode surface. However, this is different so I think applying mechanical mixing by magnetic stirring might enhance the adsorption efficiency of the WE. However, I am not sure what is the good rpm range for it which will not interfere with the electrosorption process.

Thanks!

P.S. I am not an electrochemist, so this might sound silly for the experts.

Hi, I'm working on a mechanical behavior of a new material analytically. For the purpose of verification, I need to obtain stress distribution on the cross section of a curved beam with rectangular cross section. Due to the lack of familiarity with Abaqus, I can't obtain it. How can I find it?

Hello

To validate the results of modeling by Abaqus software with experimental results, how can estimate the Chaboche hardening coefficients from the hysteresis curve?

The material is steel.

Dear fellows,

i am looking for an elasto/mechanochromic material that can undergo color change already at low applied mechanical load. Ideally the color change is reversible upon unloading and color change in visible light spectrum.

No matter if the material is polymer, metal, or ceramic.

I am very thankful for your help or hint.

kind regards

Al.

We are working on the frictional mechanics and need to see this source.

Hey there,

I want to simulate & analyze the fracture and fatigue (crack growth) in the rear axle housing of heavy tracks (Volvo company) in Abaqus.

My question is which method is suitable for this research and how I can find the geometry and the mechanical & fatigue properties for this specific vehicle?

(If there is any related paper/thesis or anyone can help me, please let me know.)

Thank you

Hi all,

I am dealing with quasi-static compression simulations on topology-optimized lattice structures using the Abaqus Explicit solver.

By the way, I have not modeled material failure model for several reasons and the material model I've used includes Johnson-cook plastic parameters for AM-SS316L. Now here is my question:

How important and effective is modeling material failure in this case? does it effectively change the stress-strain (force-displacement) curves trend?

If yes, what is your suggestion for material failure model of SS316L in Abaqus? Is there any easier way rather than finding J-C damage parameters for SS316L?

It would be great if anyone can help me to find these parameters.

Regards,

Mohsen

i want to move a parabolically varying load according to time in ansys apdl. this should be written with codes because i want to apply this load for many cycles.

Hi everyone,

To put this in context, , I am making a Matlab algorithm for topology optimization that consider fatigue breaking. I am basing on the Ole Sigmund algorithm, which discretices the

**2D piece**into a rectangular mesh.For analysing the fatigue resistance of a piece candidate (discreticed on little squares), I need the stress tensor everywhere, so I decided to compute the

**stress on the center of each squared element, with FEA**analysis, because displacements of the nodes are already computed .Then, I apply the standard

**4-node quadrilateral element**stress analys: I know the 2 displacements (u,v) of each 4 node, and I apply interpolation to know the deformation on the center of the element, and so the**3 stress components**. I do it with the B matrix and C matrix:*B=0.5/l*[ -1 0 1 0 1 0 -1 0; 0 -1 0 -1 0 1 0 1; -1 -1 -1 1 1 1 1 -1];*

*(l=side of the element)*

*C=(E/(1-nu^2))* [ 1 nu 0;*

*nu 1 0;*

*0 0 (1-nu)/2 ];*

*Stress=C*B*nodes_displacements*

The problem is that once I compute those stresses, and so the Von Misses stress, the

**final result doesn't seem to be correct, mostly on parts of the piece being flected.**I also tried taking the 16 closer elements for interpolating the stress on the center of the element, but it didn't work either. I did that last thing with a much bigger B matrix, that has as "input" the 32 displacements of those 16 points around the element:

*B=[ -0.0013 0 0.0352 0 -0.0352 0 0.0013 0 -0.0117 0 -0.0117 0 0.0013 0 -0.0352 0 0.0352 0 -0.0013 0 0.0117 0 0.0117 0 -0.3164 0 0.3164 0 0.3164 0 -0.3164 0;*

*0 -0.0013 0 0.0117 0 0.0117 0 -0.0013 0 0.0352 0 -0.0352 0 0.0013 0 -0.0117 0 -0.0117 0 0.0013 0 -0.0352 0 0.0352 0 -0.3164 0 -0.3164 0 0.3164 0 0.3164;*

*-0.0013 -0.0013 0.0117 0.0352 0.0117 -0.0352 -0.0013 0.0013 0.0352 -0.0117 -0.0352 -0.0117 0.0013 0.0013 -0.0117 -0.0352 -0.0117 0.0352 0.0013 -0.0013 -0.0352 0.0117 0.0352 0.0117 -0.3164 -0.3164 -0.3164 0.3164 0.3164 0.3164 0.3164 -0.3164 ]/(2*l);*

So my question is, what would be the simpliest way to fix this problem, and so to get the correct stress values?

I would prefer a way to fix it using only the 4 nodes around the element, because using 16 makes everything more complicated.

Thanks a lot for your answers.

Hi Everyone,

My attempt to use the drapability and stretching behavior of knitted composites(just fiber without matrix) in die forming. At this moment, I am only interested in the behavior of the fiber.

I ran 2 models (geometrically, constraints and interaction are identical).

Job 68-

Material model used (Steel with plasticity defined).

Results: Are converging. The behavior is as expected.

Job 69- Material model used (Carbon fiber-MAT-1 in .inp and material orientation defined based on texgen software algorithm). Added orientation by calculating the normal for each element using the node data. I have defined the material parameter based upon the property sheet from attached Hexcel-tow data.

The error I get is ratio of deformation speed is too high. I have tried a number of possibility as mentioned in this forum earlier. Any help would be highly appreciated:-)

-Sangram

I want to measure the hardness of particles that are smaller than 120 micrometers. Do you think we can use depth sensing nano indentation method to measure the hardness of this material?

The simulation involves Rigid body + Polycarbonate Flexible body. The Flexible body penetrates into the rigid body upto some extent and doesn't show up any stress and plastic strains. But when reversed the conditions, i.e. Fix the flexible body and drop rigid body onto it, stress and other results come up, Why does this happens?

I am writing a new plasticity model in Ansys Explicit Dynamics using AUTODYN as solver for Bilinear Isotropic Hardening model but any how unable to add this particular material model code, as I need MATDEF code for above model.

It will be a great help if anyone can help me to write that particular code. So as to define my model and get in continuation with my research.

Hello, I am performing an undergraduate finite element analysis research project, and my current task is to find the shear center for an asymmetric C beam. Out of curiosity, how does one go about doing this? (picture of profile attached, I am also just taking a mechanics of materials course at my university as we speak)

I wish you all a wonderful day

There is an open access journal (IJCESA) to call for research paper related to the civil engineering.

The journal is related to structural engineering, construction technology, building materials and structures, coastal and harbor engineering, construction management, earthquake engineering, environmental engineering, renovation of building, geotechnical engineering, highway engineering, hydraulic, road and bridge engineering, transportation engineering, tunnel engineering, urban engineering, water resources engineering, urban drainage and etc.

If you are interested, or if you want more information, you can visit our website: https://www.ijcesa.com

We are preparing a material list for a low temperature service (-40 degree C) due to natural gas choking downstream a drain valve. We need to choose the accepted material to suit this application other than ASTM A105. Is there any reference standard which explains the material temperature limitation for low temperature service?

If global warming cannot be resolved by controlling/minimising gas emissions, then extraordinary measures may be the only viable options, one of such ideas is placing a solar shield between the sun and earth at the L1 lagrangian point to obtain a reduction in solar insolation . It may sound crazy, more like science fiction to know that a disk of 2000km in diameter would be necessary to reduce solar radiation reaching earth by 1.7%. I wonder about the sort of stresses that would be experienced by such an enormous body. Also, what sort of materials' properties would be required to withstand the conditions at L1, for example solar radiation, other rays. While it is possible to calculate the disk's orbital velocity around the sun, its angular velocity (around its axis) is difficult to calculate. I would be grateful if those with relevant experience could share their thoughts about how such calculations could be achieved.

This problem could be used as reference.

The toughness and resilience are calculated when tensile load is applied. Will a material absorb same energy when a impact load is applied such as bullet fired on the material front face? Which material will absorb more energy; whose resilient modulus is more or whose toughness modulus is more or a material which becomes strain hardened?

I have a Scenario where my lock nut is tightend using a prevailing torque of 14 Nm (as mentioned by the manufacturer) on to the rotor placed between bearings (But the tightening direction and the rotor rotating direction is same unfortunately). The lock nut is loosened after particular life cycle of usage as the rotor rotates with a acceleration of 1230 rad/sec and every time it starts, the sudden acceleration loosens the lock nut. Is there a simple approch to calculate a appropriate prevailing torque for this situation, so that the lock nut does not loosen up when the rotor starts accelerating towards it's max RPM of 9400 in 1 second?

Hello,

A very general question is ahead.

Under what particular loading, is the infinitesimal rotation tensor nul ?

This question requires explanation. Discussion on the second day of Galileo’s Two Chief World Systems raises the point.

Simplicio, taking the position of those opposed to Copernicus, doubts the Earth moves; if Earth moved it would have to move at too great a speed. Sagredo and Salviati say this objection has no merit. The fixed stars have a radius far greater than the Earth, and yet the implied speed, much greater than that of the Earth in the Copernican conceptual reference frame, does not undermine the belief of the anti-Copernicans in their objection. Here is an inconsistency.

The inconsistency is not encountered in modern times that takes for granted the heliocentric model of the solar system. This argument, based on the large radius of the distant stars, is one not usually encountered. One supposes that is so, because it is unnecessary. But then the question arises. Does society lose or forget these old insights that are discarded once new conceptual reference frames take hold? Or, perhaps, is nothing lost?

Hi everybody

I'm using abaqus dynamic implicit solver to analyze hip joint. There is not problem like this with static step. but i have to use time depended loads. so when i use dynamic implicit; there are stresses only in force applied area but no stress or displacement in anywhere else. i also tried with dynamic explicit step and concentrated and pressure loads but the problem didnt solve.

i've used frictionless surface to surface contact and fixed a region far from load applied area. and material properties defined by mimics software.

i'll also add a photo and abaqus files fore details. thanks alot for your help.

A simple crack system (

*Figure***1**) can be readily studied to estimate the Hertzian conoidal crack angle and length, and also the stress intensity factor.This is a 3

*-D*brittle elastic half-space on the flat boundary*Ox*1*x*3 of which a rectilinear contact pressure along*Ox*3 is exerted by a cylinder whose axis is parallel to*x*3; the cylinder lies along Ox3 on the flat boundary. A planar straight-front crack inclined by an angle*θ*with respect to*x*1*x*3 is present under the action of the load along*x*2 due to the cylinder. The relevance of this modelling may be understood as follows. A slab of cylinder with thickness*dx*3 at spatial position*O’*(0*,*0*, x*3) exerts elastic fields (displacement and stress) proportional to those of a point load at*O’*(proportionality coefficient*dx*3). Physically, this corresponds to the action of a spherical indenter to which is associated a conoidal fracture surface for sufficiently large load (Roesler (1956) as quoted by Frank and Lawn (1967)). The coalescence of conoidal cracks from different slabs of cylinder along*Ox*3 would produce planar fracture surface envelops parallel to*x*3 at large crack lengths. Therefore, we expect the modelling in**Figure****1**to provide the experimentally observed fracture surface inclination angle*θ*and crack length*l*as a function of critical load*P*by both a spherical indenter and cylinder. This is the essence of the modelling depicted schematically in**Figure****1**.What is the tensor type for Green Lagrange strain tensor and 2nd 2nd piola kirchhoff tensor?

Stress and strain are called 2nd order tensor because they follow the transformation rule: sigma`= R * sigma * R' where R is transformation matrix.

Deformation gradient, rotation matrix and 1st piola kirchhoff are called two point tensor because they relate two configuration. For example deformation gradient is: F(iJ) = xi * XJ where * is dyadic or tensor product and XJ and xi are the element before and after deformation.

What about Green Lagrange strain tensor and 2nd piola kirchhoff tensor?

which they do not change with element rotation

Using damage model includes the relation between the effective and true stress. The true stress-strain curve is the stress-strain curve measured directly from experimental tests which could include softening part. While the effective stress-strain shouldn't have. Is that right?

I am trying to model the strain-softening behavior of rock mass using UMAT subroutine. And, I am applying the 'static Riks method'. My model is running fine in abaqus under small loading. However, when comparatively large loading is applied the analysis is being aborted after 18% load application with an error msg, 'THE SOLUTION APPEARS TO BE DIVERGING. CONVERGENCE IS JUDGED UNLIKELY'.

I have checked the .msg file, .log file and the UMAT subroutine file, but could not find any thing helpful.

Kindly give me some suggestions for solving this problem.

Regards,
Dipaloke

How the total potential energy is a unique function with respect to semi-tangential rotation?

Also how the tangent stiffness matrix of space elements based on semi-tangential moment is symmetric?

Also when referring to variation in the work (virtual work), we use virtual rotation not rotation variation?

Thanks.

The balance laws could be defined in term of Cauchy stress and 1st Piola-Kirchhoff stress tensor as follow https://en.wikipedia.org/wiki/Continuum_mechanics

But could I define it in term of 2nd PK?

For close shaped section, polar moment of inertia can be calculated from perpendicular axis theorem (adding both the 2nd moment of area in cross sectional axis). But how to calculate polar moment of inertia (2nd moment of area in perpendicular direction of the cross section) of I beam?

Hi All

For an ndof vibration system of mass and dampers, we know the equation of motion for imposed force.

but in finite element codes, it is also possible to apply a constant displacement and calculate the reaction force in the fixed end of the system as the response function .

Anyone could help with how to write the equation of motion for such a vibrating system ?

It's seems that addition of carbon atoms increase the hardness by solid solution strengthening. However I do not know why it will have more effect on ferrite than on Austenite.

Can some one give me details for the application of QUICK scheme to 2d lid driven cavity?

Best Regards

I encountered a return-map technique in many papers but I do not understand how it works.

I got an error in Ls Dyna after solving, says that *** improper format** and error in keyword.

I am modelling the heat transfer analysis of a wire electrode during the wire EDM process in ABAQUS. Can anyone please help how to apply the wire pre tension in the model as a boundary condition. Do I need to use coupled temperature displacement analysis to apply this mechanical constraint. I am attaching my model of wire electrode.

Thank you in advance.

I don´t have any idea about these two add on softwares for fatigue calculation. I am also new in FE simulation. Any comments or suggestions about the operating of these two softwares.

Major question.. give me your logical definition and whats the deference in application....

The beam has unsymmetrical section and is simply supported at its both ends and subjected to forces and moments in all 3 directions at a point.

I am working on cohesive contact(Between two Aluminium bars). I just have some questions that I am wondering if anyone can help me by answering them.

1. How can I find the the parameters in traction-separation: Knn, Kss, Ktt ( should I consider module of shear and elasticity for them?)

- In damage initiation: normal, shear 1, shear 2 (would I consider tensile and shear strength for these values?)

- In damage evolution: fracture energy. mix-mode ratio 1 and 2

2. From where i can get this parameters ??

I'm looking forward to hearing from you soon.

Thank you,

The function assumes a direct and reverse law. What do we know about the inverse function? Never mind. This is just the shadow of the direct function. Why don't we use the inverse function, as well as direct? ------------- I propose the concept of an unrelated function as extended concept of reverse function. ------------ There is a sum of intervals, on each of which the function is reversible (strictly monotonic) -nondegenerate function. ---------- For any sum of intervals, there is an interval where the function is an irreversible-degenerate function.

It seems that when an element (let's say an infinitesimal 3D cube) on earth is not subject to applied forces, the assumed stresses in all dimensions are zero. Why don't we take the atmospheric pressure into account?

In the case of a material whose strength is dependant on the confining pressure, will ignoring atmospheric pressure give a false indication of its actual strength?

There are control strategies like LQR, Positionfeedback control, Negative velocity feedback control, etc.

Which one will provide better active control of vibration ?

Normally, representative volume element (RVE) of the composite is independent of geometry. There are several homogenization methods available that defines regular shaped like rectangular, quadrilateral with inclusions of rectangular,circular,ellipsoidal, spherical shapes. Is there any analytical methods defined for irregular shaped RVE?

Hello everyone,

The strain energy of Abaqus neo-Hookean material is:

U = C10 * ( Ibar1 - 3 ) + ( 1 / D1 ) * ( Jel - 1 ) ^ 2

If D1 = 0, then stress values will become infinite. But, there are examples in Abaqus Documentation that D1 is assumed to be zero.

What happens when D1 is set to be zero in Abaqus neo-Hookean material?

Does it change the strain energy function to avoid infinite stress?

What does it mean when D1 is zero?

I am doing quasi static and high strain rate compression and tension test but the yield value are different. Compression yield is grater than tensile yield. What is the reason behind it.

Eigenstrain reconstruction of residual strains in an additively manufactured and shot peened nickel superalloy compressor blade

E Salvati, AJG Lunt, S Ying, T Sui, HJ Zhang, C Heason, G Baxter, ...

Computer Methods in Applied Mechanics and Engineering 320, 335-351

Stress fracture is associated with significant morbidity, attrition, failure to complete training, failure to return to pre-injury level activity as well as increased likelihood of re-injury, specifically within military populations. Pathogenesis of stress fracture is multifactorial in nature. The incremental rate of progression in both volume and intensity of high impact physical activity leading to a breach the bones capacity to tolerate repetitively applied mechanical loading such that repair is exceeded by damage, however, the precise mechanisms are yet to be confirmed.

Stress fractures require some of the longest recovery times and is reported to range from three weeks to several months. The Professional, legal and moral responsibility to investigate causation, management and mitigation of these costly injuries are the property of both organisation and individual clinician.

Our stress fracture protocol consist of 4-6 weeks partial weight bearing, once pain subside, commence 3 phases Rehab programme. Therefore, I am inviting your opinion regarding effective stress fracture rehabilitation method to prevention as well as intervention to enhance bone healing process.

hello,

In which case and conditions could we consider a 2 DOF system (2 mass 2 springs) like a single DOF system.

thanks