Strain Definition and 413 Threads

What model correctly predicts the sensitivity of a resisitive wire straing gage to applied strain? This question is motivated by an an old pamphlet found in a used book store, "Theory Of Strain Gage Flight Test Instrumentation" by Eugene Frank, 27 May 1946. The gage factor of a strain gage...

This is regarding youngs elastic modulus I need help as I am trying to figure out the stress and strain of an elastic band when a force has been applied - in youngs modulus. Does anyone know how to go about this?

Homework Statement Establish the constitutive relationship for the cantilever beam material, i.e., provide an empirical formula for the relationship σxx=σxx(εxx) and generate a plot of this relationship. What is the cantilever beam material? Homework Equations This is a pure beam bending...

Where can I buy strain reliefs? All I could find on Amazon are 6,000 different kinds of RJ-45 booties, which are not what I'm looking for. Mouser is impossible for things like this unless you already know exactly what you are looking for. I quite like the strain relief used on the LeCroy...

Is anyone familiar with the Roark's text that can clarify some terms for me? I am trying to clarify what Roark is referring to in the above mentioned text in the section on short beams (in the 5th edition 7.10 and in the 7th edition 8.10). Throughout the text, he uses the terms "span" and...

Does anyone help me to solve this problem in the attached file? When I solved this problem, I got wrong answers. Attached file is the image file with the problem and answer. (Question No.3) I think I have to find allowable shear stress of Pin A to find the safety factor of this pin...

Hello all, I would like to know if there are strain gauges out there that could be used for small cylinders. To describe the problem/design more thoroughly, I am trying to design (or purchase) a cylinder no bigger than 3mm. When the end of the cylinder is compressed (across the circular...

So I am currently using a high temperature epoxy based strain adhesive on a polyimide coated single mode fibre. This however gives rubbish results in terms of creep at anything above 160 deg C. Does anyone have any experience with this type of problem at all? I know that there are...

Hey guys so i did a tensile test lab and got the following results from the strain gage: SecondsElapsed Strain u 0.1 0 1.1 1 2.1 1 3.1 0 4.1 0 5.1 1 6.1 1 7.1 2 8.1 5 9.1 9 10.1 47 11.1 129 12.1 209 13.1 278 14.1 335 15.1 386 16.1 434 17.1 482 18.1 529 19.1 579...

Hello, I am doing a project where I have 4 strain gages (in a full bridge Wheatstone configuration) and I am continuously recording their output voltages. These strain gages have been installed on an aluminum bar and are recording bending. My question is how to I convert the output voltage...

If I have a wide beam, parallel to the x axis, with its COM at the origin, then I want it to curve about the y axis, what would the elements of the strain tensor be? I have come to the conlusion that the beam would, for example,contract above x-axis and expand below it. But I don't know how...

Question The compound bar is composed of Aluminium surrounded by High Density Polyethylene Al= E = 69x10^9 Pa Al= r = 0.035 m HDPE= E = 0.8x10^9 Pa HDPE= r = 0.055 m The compound bar has a load of 75000N applied evenly to each of its ends. Part 1. Find the change in...

Hi all, I have a question regarding deformation analysis. For materials with non-zero Poisson's ration, when is it justified to use plane strain analysis rather than three-dimensional? Perhaps one case is when we are going to analyze a thin sheet. Are there other cases too? Thanks, Hassan

Hi Guys, I'm wanting to measure deflection in an injection mould tool. I'm planning on using strain gages to measure the strain in the tool under injection pressure. Is there a way I can use these strain readings to calculate the deflection in the plates? Thankyou for any help. :)

Homework Statement A three-legged stool has one leg of aluminium (E = 7 x 1010 Pa), one copper (E = 11 x 1010 Pa) and one of steel (E = 20 x 1010) Pa. The legs have the same dimensions. If the load on the stool is at the exact center, a. Which leg is under the greatest stress? Explain why b...

I have a few strain gauges that are going onto the suspension of a race bike. I've never installed these things before. While I have found a lot of information on installing them, I am having a hard time finding many adhesive and chemical options. It seems a lot of them are non-permanent, or...

Does anyone know where I can purchase a torsional strain gauge? Website? Company? Thanks

Compute the maximum longitudinal force that may be supported by a bone before breaking, given that the compressive stress at which bone breaks is 2.00e8 N/m^2. Treat the bone as a solid cylinder of radius 1.55 cm. The attempt at a solution I tried using the equation Max Torque = pi/4 * (r^3) *...

Hi guys i have a exam coming up soon and stress is starting to kick in. I am good with stress and strain, but I am just confused on this question and don't understand what i need to be doing. I've tried every formula and i just can't seem to get question 5 out. The answears for this question is...

Hi guys i have a exam coming up soon and stress is starting to kick in. I am good withy stress and strain, but just confused on this two questions and don't understand what I am doing wrong. I've tried every formula and i just can't seem to get question 6 out. And question 5 same problem i...

[a]1. Homework Statement [/b] I thought it would be easier to post a picture since this way the drawing can be seen. I'm having a hard time deciding what angles to use with the relevant equations, see below. Homework Equations I know that: Ex' =...

Homework Statement Alright, so I have this final project in physics which was due yesterday and I'm turning it in late because i have a problem with understanding one thing. so the project it about space elevators and the teacher asked me to make calculations about what is the maximum height...

Hi, Dear all, Facing problem to understand strain energy function invariant terms A typical strain energy function consist of strain invariant can be defined as followed W(I1,I4)=C0+C1(I1-3)(I4-1)+C2(I1-3)^2+C3(I1-4)^2+C4(I1-3)+C5(I4-1), I1 and I4 are so called invariants of Green's strain...

Hello, I have a question or two about gravitational waves. My current job is basically to measure atomic strains using x-ray diffraction. I have managed to reduce the error in measurement low enough to reveal an annual sine wave in my data for a sample which should not contain any strain. I...

dear all, as a newbie in solid mechanics modelling, i always come across these few terms, Cauchy-Green strain tensor Green Lagrange strain tensor isochoric Cauchy green strain tensor. Consider a cubic, when we move the top face, while fixing the bottom face, we will able to see the...

Hi there, My teacher gave me a homework, but this Theory of Plasticity is new and difficult to me. He has calculated the strain according to path (1), now I have to do with the path (2) and (3). This is what he did with path (1): ε11=∫(1/E)dσ11 +...

Vibrations of a motor (40Hz) cause noise on the signal of a strain gauge that monitors load on a cantilever that measures periodic load changes at the rate of 1/minute. Design a filter that reduces the signal caused by the vibrations by 90%. I thought about a low pass filter that has a cut...

Hello all. I am looking over various strain gauges as I need to purchase one for my project. However, I have never worked with them before, and I cannot seem to figure out how to know its accuracy (able to detect a certain change in pressure, for example changes of the scale of 1mmHg) ...

Homework Statement [See Attachment] Given: Thickness, load, G Find:γ and horizontal displacement. Homework Equations τ=γG Angle change should be the shear strain. The Attempt at a Solution I tried plugging 800 into tau and the given value of G to get γ, but that isn't...

If a wire is stretched to double of its length.What will be the strain of wire?I need to prove it mathematically that how it becomes 1.

A strain-gauge bridge is made up of four resistive elements, each element having an unstrained resistance equal to R, as shown in the diagram below. When a strain is applied to the bridge elements R2 and R4 increase in resistance by an amount ΔR, whereas R1 and R3 decrease by ΔR, where...

Homework Statement A Steel bolt having nominal Diameter of 20 mm and a pitch of 2.5 mm (Pitch is the distance from thread to thread in the axial direction), and an aliminium tube, 40 mm OD by 22 mm ID, act as a spacer for two plates. The distance between the two plates is 0.35 m. The nut...

Homework Statement There is a 104kg uniform log hung on two steel wires, A and B, both of radius 1.00mm. Initially, wire A was 2.70m long and 2.00mm shorter than wire B. The log is now horizontal. Note that the centre of gravity (com) is not necessarily centered between the wires and the...

I can't find the THEORETICAL definition of "strain optic coefficient" online. I googled and wiki'd enough. Can someone provide me with one, please?

Hello, is the strain defined as the absolute deformation to the initial ? i.e is it always positive ?? If Yes , then poission's ration is negative for compression of ordinary materials ?

I'm doing A-Level physics and I've been answering questions on Young's Modulus. I need to be able to explain why a long, thin wire is used when measuring the Young's Modulus of a material. I can give an explanation of why stress due to the wire being thinner is greater but I don't know why...

Homework Statement A plastic ball is inflated enough to produce tangential stresses. σX = σY = 2000Kpa The radial thickness of the material is 1.2mm brfore inflation. Find the thickness after inflation if the tensile modulus of elasticity is 3.4Gpa and the shear modulus is 1.4Gpa...

Hey everyone, I'm having some trouble with my material science homework. I really have no idea where to begin: Consider a piece of beam of 1 cm in length with one end fixed on a wall and the other end free (see illustration below). If you bend the beam by applying a force at the free end...

Homework Statement http://img683.imageshack.us/img683/7060/selection001l.png Homework Equations \epsilon^{pl} = \epsilon - \epsilon^{el} \epsilon^{pl} = \epsilon - \frac{\bar{\sigma}}{E} r = \frac{\epsilon_w}{\epsilon_t}The Attempt at a Solution I'm stuck trying to calculate \bar{\sigma}...

Dear all, I would like to know from you the solution about this problem (which is not a homework, but a topic of my Master thesis!): I need the strain energy density related to a circle of radius r0 centered in an arbitrary point of a square plate, under the boundary conditions described in...

Homework Statement Homework Equations \gamma_{max} = {\left|{\epsilon_1} - {\epsilon_2} \right|} The Attempt at a Solution I calculated the maximum shear strain to be 200 \mu. For the angle, I don't know exactly how to go about finding it. However, the solution says that the angle is...

We have 2D point coordinate before and after experiment(you can see the attachement), now we want to get the contour line of effective strain after deformation, is there any method or software to achieve it?

Question from one of my exams,I am lgoing crazy becaue this is against everything I understand. Please please please help me : http://imageshack.us/f/189/examh.jpg/ Basicaly,I need to found what the "0" degree shows me on elongation. As I look at the hole in the figure,I see the pressure...

Hey, everyone. I'm new here. This is a continuum mechanics question. If it's the wrong forum, please let me know, of course. The question is pretty simple, but since I haven't been able to find an answer, I'm looking for "crowd help". Green strain \mathbf{E} is usually defined implicitly by...

Homework Statement The question is: calculate the total amount of strain at fracture? How much of this is recoverable strain? Explain your answer Homework Equations strain = (change in length)/ (initial length) The Attempt at a Solution I'm not sure about my answer but i just...

Hello Folks, I'm after a little help here, I've been asked to calculate the maximum strain a beam is under at a certain deflection, for a part we are planning to get Rapid Prototyped It is a rectangular beam attached to a wall at one end I have the material data sheet for the material...

Homework Statement This is just a simple questions concerning the method of obtaining nominal stress and nominal strain. From various sources on the net they refer to nominal stress/strain as engineering strain therefore can I just use the simple equations for stress and strain? In this...

Hi All I am a mechanical engineering student and require to attach a full Wheatstone bridge to the underside of a cantilever beam, 103x27x5 mm LxWxH. Where would be the best location to mount the gauges?, also in which orientation should I mount them? All parallel to the length of the beam...

Imagine you have a cylindrical plug of plastic that you press fit into a hole. I need to determine the raidal pressure, radial stress, that the plug exerts on the wall of the cylinder. Here is what I have so far. Lateral Strain = (d_initial - d_final) / d_initial\ From what I...

Hello, I have problem with understanding the concept of energy of deformed body. As far as I know, Clapeyron's theorem states that elastic energy of deformed body is half the work done by external forces; this are surface and body forces which deform the body. Then, I wonder, where has...