# Tagged Questions

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### Momentum equation in a Lagrangian configuration

When writing the momentum equation in a lagrangian configuration is the the stress tensor used the first Piola-Kirchhoff stress tensor or the nominal stress tensor (which is the transpose of the 1st P-...
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### For a cantilever beam, is bending stress linearly proportional to elastic deflection?

Let's say I have a cantilever beam (a beam with a fixed support on one end only) and introduce a downward point force (by hanging a weight on it or something) at some constant distance from the ...
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### Breaking strength of wet paper/cloth

In the Hollywood movie, Shanghai Knights (pardon me for the non scientific citation), Jackie Chan states that 'wet cloth' does not break easily. How true a fact is this ? We know from common ...
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### High pressure vs low Mises

I have two high Young modulus materials, and a small layer between them which material have a low Young modulus. I apply constraints on one side and make a compression. Analysis gives me low von ...
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In a prismatic beam subjected to 2D loadings, Is it possible that absolute maximum shear stress occurs at the point due to maximum bending stress (due to stress transformation)? Or that absolute ...
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### Confused about shear elasticity and complementary shear stress

I am a self learner of continuum mechanic. I am confused about simple shear stress in situation similar to figure 1, in case $F_\textrm{ext}$ is caused by external perturbation by i.e., human, what ...
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### Phonon softening explanation

Is there a simple, intuitive answer of why phonons soften with strain? I am aware of the GrÃ¼neisen parameter but it just tells us there is a negative sign.
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### Is it possible that Cauchy stress be asymmetric?

According to conservation of linear momentum and angular momentum, one can derive that Cauchy stress tensor is symmetric and hence has only 6 independent components. Is it possible that, when breaking ...
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### How to model analytical expression for spring constant $k$ for certain structure?

In the deflection of beam, I learned that $$\delta y=\frac{FL^3}{3EI}$$ where $$I=\frac{h^3w}{12}$$ Together they comprise $$F=\frac{Eh^3w}{4L^3}\delta y$$ How do I apply to four beams? is ...
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### determining the stress of a beam

I have a question regarding a beam. I first consider a force applied to both ends of a rectangular beam which is perpendicular to its cross section with dimensions w (width) and h (height). The length ...
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I completely disagree with the following calculations: Based on my understanding, there is no force either internal or external applied to the Green bar, so it should be 0N. The reaction (internal) ...
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### Flow Curve - Plotting Shear and Strain Rates at Different Pressures and Flow Rates in a Capillary

So I'm not really asking for a solution but more clarification on this type of problem since I'm kind of confused on the concept. So i have two capillaries of a different diameters and lengths. Im ...
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### Why is the Elastic Modulus of concrete smaller than that of steel?

I am trying to get a basic feel for what the Modulus of Elasticity means for different materials. My understanding is that since E = stress / strain, a higher E ...
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### Linear vs non-linear (finite) strain

I have a somewhat non-specific question regarding strain in materials. What I understand currently -Linear elasticity or infinitesimal strain theory is an approximation of finite strain theory that ...
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### Which area to be considered in calculating stress?

During the calculation of longitudinal stress, we say that stress is equal to the magnitude of applied force divided by area of cross section. However, is this area of cross section, the cross-...
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### 3D beam deflection

How can you get formula for 3-dimensional beam deflection at the free end of horizontal cantilever due to the cantilever's own gravitational load? I assumed E= 160GPa, $\nu=0$, $\rho=2330kg/m^3$, ...
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### Atomic Stress (Virial Stress) and Harmonic Springs

The general context here is polymer physics. The stress tensor in a bead-spring simulation can be easily computed using the Virial Stress (which may be named the Kirkwood formula, or the Doi-Edwards ...
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### Pressure vessel analysis of transversely isotropic multilayer material

Suppose I have a transversely isotropic, hyperelastic material with known strain energy that is a fibrous composite. I am interested in an explicit formula for the displacements (so I can get the ...
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### Question regarding the use of the Green-Naghdi Objective Stress Rate

The equation for the Green-Naghdi Stress Rate reads: $\boldsymbol{\sigma}^{GN} = \dot{\boldsymbol{\sigma}} + \boldsymbol{\sigma}\cdot\boldsymbol\Omega - \boldsymbol\Omega\cdot\boldsymbol{\sigma}$ ...
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### Why do chocolate bars usually break at the cleavages?

Why do chocolate bars usually break at the cleavages? The chocolate bar is less thick at cleavages. How can we relate thickness and fracture point of chocolate bar?
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### Why is maximum shear stress at 45 degrees instead of near 0?

I think I might havr an immensely stupid question but it's really bothering me so please be patient. I am not physicist smart. Look at this guy's question: https://www.physicsforums.com/threads/mohrs-...
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### Equation Governing Small Lateral Deflections z of a Uniform Membrane

The equation governing small lateral deflections z of a uniform membrane subjected to a lateral (dimensionless) pressure p is given by  \frac{\partial^2 z}{\partial x^2} + \frac{\partial^2 z}{\...