Strain Definition and 413 Threads

Homework Statement I have the following table Load 25 50 75 100 125 150 160 170 Extension 0.38 0.75 1.15 1.53 2.8 8.6 15 28 and I need to: 1. Plot the stress – strain or (load-extension) graph and determine (a) Approximate value of the elastic limit (b)...

Hello, recently I became interested in some basics of material science and there was one thing that I did not really understand. What is the difference (or what are things in common) between creep and strain rate sensitivity? I read about it in connection with indentation. - To measure the...

Is strain always recoverable in a viscoelastic solid? For instance, I thought in the single-branch Maxwell model, there was unrecoverable strain ... or am I wrong? And then if you use a two branch Maxwell model (one spring, one spring + dashpot), all strain must be recoverable, correct?

Dear forum people The new position of the carbon atoms under uniaxial strain r in the framework of elastic theory is shown by the following equation: ri'=(I+ε).ri in which ri and ri' are the position of the carbon atoms before and after the strain is applied, respectively. I is the unit matrix...

Homework Statement Homework Equations The Attempt at a Solution Not sure if I'm on the right track here at all. p=40*10-6*6*10-3*290*109/1=69600 Pa=69.6 kPa

Can we plot stress-strain curve if we only have yield strength, tensile strength, and elongation data? For example if i have: Yield strength = 300 MPa Tensile Strength = 600 MPa Elongation = 50% How to plot the stress-strain curve? Thanks

I am a part C mechanical engineering student and require some advice for my individual project, which is based on the high strain-rate testing of a particular glass filled composite material using a split-Hopkinson pressure bar (SHPB) experiment. I gathered the results on a SHPB test rig and...

I want to create stress/strain curves for Higher Strain Rates from an available stress/strain curve? I am interested on the mathematical formulation aspect to generate a Dyna Material card.

Homework Statement Just wanted to check my work on this one. An aluminum wire is clamped at each end under zero tension at room temperature. The tension in the wire is increased by reducing the temperature which results in a decrease in the wire's equilibrium length. What strain (ΔL/L) will...

Homework Statement For a crystalline metal material - Elastic modulus E - Poisson ratio v - A table with test data of stresses vs. total strains, from a monotonic uniaxial tension test, which generates a stress-strain curve. How would you use this data to find the corresponding pure shear...

Using R = ρL/A, I am trying to get this formula, which is the change in resistance due to change in length, area, and resistivity. ΔR = (∂R/∂L)ΔL + (∂R/∂A)ΔA + (∂R/∂ρ)Δρ I understand the above conceptually, but I am confused about why we are multiplying by terms ΔL, ΔA, and Δρ. Intuitively, I...

I need help understanding a passage in my textbook, where the form of hookes law in continuous elastic media is explained. It says: "The absence of internal directions in isotopic matter tells us that there are only two tensors available to construct a linear relation between the the stress...

Homework Statement A dog-bone specimen made by aluminum alloy is used for tensile testing by a force of 4000N via two steel pins. The dimension of the specimen is shown in the following picture; the thickness of specimen and the length of pins are 4mm and 8mm, respectively. The mechanical...

Homework Statement Given your average Wheatstone Bridge with R1 R2 and R3 unknown resistor values and R4=RG= strain gauge, how to solve for the resistor values given only input voltage and the value of the resistances between the resistors?[/B]Homework Equations Not Sure[/B]The Attempt at a...

It's about shear stress and strain. We are talking about Newtonian fluids, a situation where we are lubricating a rotating shaft with oil. I cannot understand what we are measuring that we use as the strain. SOLIDS. As far as I know we can say: Stress (F/A) = G x (Δ l / l) Where G is shear...

I am so confused about these quantities. For many theoretical setups you assume a linear relation (elastic materials) such that for example if you press on the side of a rectangular box, it makes the box contract in the normal direction to the induced stress. Also the box will expand in the...

Homework Statement Hi Everyone, I am going to be doing an experiment soon using strain gauges on a beam and I will have to, among other things, calculate the direction of the maximum shear strain with respect to the axis of the beam. I am trying to find the correct equation to use. Homework...

How can we determine which curve has larger slope just by looking at curves. http://www.meritnation.com/img/shared/userimages/mn_images/image/a_2_12_2.png Which curve has larger slope?

Homework Statement A 2.75 KN tensile load is applied to at test coupon made from 1.6 mm flat steel plate (E=200 GPa, v=0.30). Determine the resulting change in the 50 mm gage length. Homework Equations εx = (σx/E) + (-Vσy/E) - (Vσz/E) εy = (-vσx/E) + (σy/E) - (Vσz/E) εz = (-vσx/E) - (Vσy/E)...

Homework Statement hi guys i have a sheet of i have the W,L and T a force and also the elastic modules etc now my issue is i need to find the strain i have the stress etc but the is no extension figure given i have the usual strain equation e=x/l can anyone point me in the right direction in...

Hi Guys, I have been given a lab report to complete on Torsion of a beam. - Beam was subjected to torsion under increments of weight - Strain gauge rosette was placed, A B and C where there is 90 deg between A and C, B at 45 deg in between. - The angle from Gauge A and the "x" axis was given...

Homework Statement Hi, I am doing some things with Mohr's circle. I am trying to find the direction of max strain but I am a bit confused. How can I do this? Homework EquationsThe Attempt at a Solution I always assumed that the max strain occurs at 90O from the normal axis or 45O in real...

Homework Statement I have used a strain rosette with two gauges at 0 and 90 degrees to find strain on a beam under force and an trying to plot Mohr's circle for the problem. As the gauges are at right angles finding the xx and yy strain is easy but I am lost about how to find the xy strain...

Lets take an example of a person pushing a thick wall, of course no deflection in the line of action of force is seen but can strains be induced in it, like surface slips?

Hi, Do helical springs have hysteresis. Say I do an exercise of plotting deformation Vs load curve of a helical spring, one way will be starting from load zero and increasing till the spring achieves solid length. The other way will be loading the spring till solid length and measuring...

Homework Statement The component shown in Fig 1 is made from a material with the following properties and is subjected to a compressive force of 5kN. Material Properties : Young’s Modulus of Elasticity – 200 GNm-2 Modulus of Rigidity – 90 GNm-2 Poisons ratio – 0.32 Calculate : (a) The stress...

I understand that too much close reading will strain the ciliary muscles of the eyes. But what about small fonts? The contraction of the ciliary muscles is dependent on the distance not font size. In other words, it is better to read from a closer monitor with bigger font or from a further...

I have a conceptual misunderstanding it seems. Poisson's ratio is the ratio of elastic strain deformation of the transverse and longitudinal components. That being said, if I were to induce thermal stress (heating up) to a rod by keeping its ends (longitudinal component) rigid, would there be a...

Before yield we know that stress/strain= E. Can we obtain the same E if we substitute true stress and true strain in the equation? Why

Ever since I learned that short-sightedness is due to the eyeball being too long, and far-sightedness is due to the eyeball being too short, I've wondered what the point of avoiding eye strain is. How could straining the eyes possibly have the effect of changing the length of the eyeball? By...

Homework Statement Poisson's ratio v is the negative ratio of the transverse strain to the axial strain. For an incompressible (density doesn't change), homogeneous (everything is the same molecule), isotropic (it doesn't matter which direction you pull or push on it, it will act the same way)...

Hi, I have some experimental data and I am interested to use this data to calculated modulus of elasticiy (young's modulus) and Poisson's ratio. The material for which the data is given in an anisotropic material, therefore I need to calculate modulus of elasticity and poisson's ration is x,y...

For some metals and alloys the region of the true stress–strain curve from the onset of plastic deformation to the point at which necking begins may be approximated by σ=Kεn where n is strain hardening exponent. I wonder whether this equation can be applied to engineering stress-strain curve or...

Hello I'm having trouble wrapping my head around finding things from stress strain curvesI need to find: Elastic modulus (Young’s modulus) •Yield strength •Tensile strength •Uniform and total elongation (ductility) elastic modulus I think is 1240/0.02 = 62000 but I'm unsure of how to find...

I am struggling with a question in my coursework, and would appreciate some guidance. The question is: The component shown in Fig 1 is made from a material with the following properties and is subjected to a compressive force of 5kN. Material Properties : Young’s Modulus of Elasticity – 200...

Hello, I'm trying to design a strain gauge load cell for force measurments. I have few questions regarding that. Q1: how to calculate the minimum froce that my load cell can detect? Q2: how to calculate the FSO(full scale output) of my load cell? Q3: Is there any way to measure the...

Hello, I would like to know, how to calculate the number of grid lines( or loops) in a strain gauge. I'm trying to calculate the output form the each grid lines. Thanks in advance

Hello, I would like to ask if its possible to apply pressure through fluid on a curved soft tissue such as silicon to measure the strain by using sensors (and what kind) such as shows in the attached image? If those were pressure sensors would they all show the same pressure or would the change...

I have gathered all the information: Span: $1991$ m Breaking Stress: $1770$ MPa Load: $370$ KN/m Drape: $201.2$ m So far, I've found the allowable stress by dividing the breaking stress by the safety factor, which is $787$MPa. Then, I calculated the total load of the bridge, by multiplying the...

Im currently studying a course on the mechanics of solids..the reference book i use is by Popov..But i can't completely understand the concept of stress in an axial loading.Like for instance. If a weight W acts on a rod(ignore the rod's weight),stress will vary point to point along the...

Hi guys. Let me just say at the outset that I know very little fluid mechanics but I keep coming back to the same issue over and over in a general relativity related problem so I figured I'd just ask the fluid mechanics question here. In countless places the interpretation of the vorticity...

Hi everyone. I feel there should be a simple answer to this but I can't seem to find anything on this. So I have a simple cantilever beam, supported at one side and loaded at the free end. I have the force displacement data and can easily calculate the stress. However, for the strain I do...

I am not a (real) engineer, but have undertaken an ambitious project which contains some technical intricacies I have to learn on the fly. My first question (of many to come no doubt) is about strain gauge load cell technology - specifically powering the device. My project requires a battery...

[SIZE="4"]Definition/Summary Stress is force per area, and is a tensor. It is measured in pascals (Pa), with dimensions of mass per length per time squared (ML^{-1}T^{-2}). By comparison, load is force per length, and strain is a dimensionless ratio, stressed length per original length...

Homework Statement What are the potential errors in measuring strain with strain gages? How can these errors be minimized? The Attempt at a Solution In my class notes, I have the four Errors. 1-Gage mounting (glue thickness & flex) Use a thin layer of glue and make sure the layer is smooth...

I'm trying to develop a Matlab Simulink model which models the relationship between the voltage applied to a motor, and the voltage across a strain gauge connected to a shaft attached to the motor. So far, I have found the transfer function between voltage and motor torque, and the transfer...

Hi, The attachment below is about strain rate in fluids*. It shows how the strain rate d\phi/dt is related to the velocity field derivative du/dx when you stretch the element in x (i.e. longitudinal strain). It has no intermediate steps, and I can't see how the angle has been related to...

Homework Statement Determine the Strain Rate for a Material Fiber in the direction of the surface normal. The Velocity Field is V=((4y-3x)i+(5x+3y)j) ft/s http://puu.sh/9hQ7Q/2bda80620f.jpg is the picture which describes a steady, planar flow where i and j are unit vectors. Homework...

A 30kg sledge hammer strikes a steel spike of 2.30 cm diameter while moving at 20.9 cm/s. The hammer rebounds with a speed of 10.0 cm/s after 0.110 s. What is the average strain in the spike during impact? 2. F = (mvf-mvi)/t S = (F/A)/(deltaL/initialL) Young's modulus for steel = 2 x...

Homework Statement A 24in diameter concrete column, at tenth story of an office building, is supporting the flat roof slab is subjected to a wind uplift load of 50.00kips while carrying a factored compressive force of 120.0kips. the column is 10.00ft long. Assume elasticity of concrete...