What is Strain: Definition and 461 Discussions

In organic chemistry, ring strain is a type of instability that exists when bonds in a molecule form angles that are abnormal. Strain is most commonly discussed for small rings such as cyclopropanes and cyclobutanes, whose internal angles are substantially smaller than the idealized value of approximately 109°. Because of their high strain, the heat of combustion for these small rings is elevated.Ring strain results from a combination of angle strain, conformational strain or Pitzer strain (torsional eclipsing interactions), and transannular strain, also known as van der Waals strain or Prelog strain. The simplest examples of angle strain are small cycloalkanes such as cyclopropane and cyclobutane.

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  1. L

    Engineering Reducing noise in strain gauge using an RC circuit

    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...
  2. U

    Effect of Strain Hardening on Yield Strength

    Homework Statement The strain hardening behavior of an annealed, low‐carbon steel is σ = 100,000ε0.2 If a bar of this material is initially cold worked 20%, followed by additional cold work of 30%, determine the probable yield strength of the final bar. Homework Equations σ=κεη...
  3. G

    How to know a strain gauge's accuracy?

    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) ...
  4. D

    Finding Average Shear Strain in a flexible connection of rubber and steel

    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...
  5. Q

    If a wire is stretched to double of its length.What will be the strain

    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.
  6. D

    Thevenin equivalent for strain gauge bridge

    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...
  7. H

    What is the Stress in a Bolt and Spacer System?

    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...
  8. P

    Stress, strain and modulus - log hung from 2 wires

    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...
  9. Femme_physics

    Strain optic coefficient definition

    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?
  10. A

    The compressive longitudinal strain

    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 ?
  11. G

    Why is strain greater in longer wires?

    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...
  12. H

    How Does Inflation Affect the Thickness of a Plastic Ball?

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  13. B

    What is the strain on a cantilever beam under perpendicular force?

    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...
  14. L

    Continuum Mechanics: Finding Plastic Strain

    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}...
  15. M

    Local strain energy density for a plate subjected to in-plane linear load

    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...
  16. D

    Strain Gauge recommendation

    Hi can someone please recommend a strain gauge to measure mass flow rate of a pneumatic conveying system. The full bridge circuit strain gauges are to be placed on a cylindrical cantilever beam with a length of roughly 160-170mm and a diameter of 36mm and made of iron. From what I have read...
  17. 1

    Relationship of applied load against beam surface strain

    Homework Statement I am working with an electronic bathroom scale and now have to find the relationship of the applied load which is mass in kg against the beam surface strain. The maximum load is assumed to be 75 kg. Homework Equations (M/I)(h/2)=Eε A picture of the beam has been...
  18. T

    Maximum shear strain direction

    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...
  19. H

    Contour line of Effective strain

    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?
  20. B

    What Does a 0 Degree Show in Elongation for Strain Gages?

    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...
  21. E

    Clarification on Definition of Green Strain

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  22. T

    Calculate the total amount of strain at fracture?

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  23. M

    Cantilever Beam - Maximum Strain @ Deflection

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  24. P

    Help Concerning Nominal Strain and Stress

    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...
  25. G

    Strain Gauging Assistance Required

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  26. M

    Radial pressrue given lateral strain

    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...
  27. N

    Strain elastic energy of a continuum

    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...
  28. I

    Strain analysis using Star rosette

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  29. A

    How Does A Strain Tensor Transform?

    Hello All, I am trying to learn the theory of elasticity from Landau's book and from the very beginning I've run into trouble. As I learned it, a (0,2) tensor T_ij obeys the transformation law T_hk=T(dx_i/dx_h)(dx_j/dx_k). But I do not see how a strain tensor can be transformed in such a...
  30. E

    Tensile Strength and Tensile Strain

    Are these two things the same? I'm looking at bioabsorbable copolymers with similar properties to the human acetabular labrum, but I can only find tensile strength values for the copolymers and tensile stress at break for the labrum. I've looked at the definitions of each it sounds like the...
  31. H

    Stress-Strain Graph:Why Plot Strain~Stress?

    I have a very fundamental doubt regarding the stress strain graph for many materials..Normally we plot strain ~stress in the graph..but it seems that stress is the independent variable and strain is the dependent variable..but still why nowhere i have found the curve as stress~strain..can...
  32. L

    Stress strain and youngs modulus

    When plotting a stress against strain graph is this the right equation that fits the form y=mx+c? I got (F/A)=y(dL/L) where F is force A is area y is youngs modulus dL is change in length and L is original length. The Y is F/A. The m is y and x is dL/l (in y=mx) is this correct? Thank you
  33. O

    Compresible volumetric strain rate-fluid mechanics

    This is not really part of my homework but I still want to drive this equation. Continuity equation: p=density D/Dt=material derivative Grad: Gradient V=Velocity vector v=volume so; (1/p)(Dp/Dt)= -Grad.V and p=m/v then, (1/(m/v))(D(m/v)/Dt)= -Grad.V Following is what I can't seem to get...
  34. M

    Need help to calculate misfit strain?

    Need help to calculate misfit strain? Homework Statement I would like to calculate the misfit strain on InP and InGaAs when InGaAs is grown on InP Homework Equations lattice constants for InP , a1= 5.8687 InGaAs a2=5.7455 ( with 25% In) The Attempt at a Solution I have...
  35. M

    How do I calculate misfit strain ?

    Homework Statement I would like to calculate the misfit strain on InP and InGaAs when InGaAs is grown on InP Homework Equations lattice constants for InP , a1= 5.8687 InGaAs a2=5.7455 ( with 25% In) The Attempt at a Solution I have calculated the lattice mismatch ratio as...
  36. K

    Engineering Strain Gauge Project Circuit Question

    Design a circuit that uses a stain gauge to create a voltage related to the strain experienced by the gauge. The strain gauge should remain electrically isolated from the ground. The DC common mode voltage should be minimized. Only stain-related signal to be measured does not have any...
  37. I

    Simple stress, strain, elongation relationship question

    Howdy ya'll, a relatively simple question, A circular bar 20mm in diameter and 1m long is subjected to an axial load of 50kN. Determine: (i) The normal stress. (ii) The normal strain. (iii) The elongation. Assume the material is steel with an Elastic Modulus of 200GPa. ok so i...
  38. J

    Chassis Stress & Strain Calculations

    Hi Guys, So I am biting off more than I can chew with my latest project.. and looking for help. I am going to fabricate a kit car chassis, The suggested material is 1' x 1' steel box section but why? Could anybody help by suggesting the kind of calculations I would have to research...
  39. C

    Proof Stress Calculation with Excel 2007: Manual or Automated?

    using excel 2007, can the construction to determine the proof stress of a material not be done manually? if so, how?
  40. M

    Can Maximum Bending Strain Be Calculated Without Knowing Young's Modulus?

    Very simply put. Is it possible to determine bending stress in a beam without knowing the young's modulus of the material used? All equations I've seen seem to include in some form an E value ( young's modulus), which is used in conjunction with a stress value to evaluate the strain.
  41. N

    Component of a infinitesimal strain tensor

    I have the folowing continuum mechanics problem which I can't solve: The unit elongations at a certain point on the surface of a body are measured experimentally by means of strain gages that are arranged at 60° in the direction of 0°, 60° and 120°. Coordinate system is rectangular Cartesian...
  42. N

    Component of infinitesimal strain tensor

    I have the folowing continuum mechanics problem which I can't solve: The unit elongations at a certain point on the surface of a body are measured experimentally by means of strain gages that are arranged at 60° in the direction of 0°, 60° and 120°. Coordinate system is rectangular Cartesian...
  43. 2

    Failure Due to Stress or Strain?

    Currently I am studying the mechanical properties of artery tissue, and was tasked with determining if the tissue fails due to shear stress or shear strain. I have always worked under the assumption that they go hand in hand with each other, but the nature of this question obviously suggests...
  44. F

    Strain on different parts of a cantilever

    Hey physics forums people, this is my first post ever and I am not sure if this is the right sub forum, but w.e, let's try this out anyways Homework Statement K so the problem is I've got a weight hanging on the shear centre of a cantilever and there are strain gauges all over it It is an L...
  45. S

    Wide Range Strain Indicator Units

    In lab for our final project, we used a Wide Range Strain Indicator connected to strain gages on a part we machined to function as a scale. The Indicator device was much like this one: http://www.datasheetcatalog.org/datasheet/vishay/3800.pdf What units would the numbers be that we're...
  46. L

    How to derive plane strain bulk modulus?

    This is a homework problem and I thought about putting it in the homework section bu since its very materials science specific I decided to put it here: For a transversely isotropic material, the “plane strain bulk modulus”, K23, is an engineering constant that is defined by the stress...
  47. C

    Relating Radial Strain to Circumferential

    Hi, I have a solid cylinder to which I have strain gauges attached to measure axial and circumferential strains. My goal is to relate the circumferential strain to radial strain and then to calculate possion's ratio. Every time I try to work out the geometry of the problem I end up saying...
  48. N

    Stress and Strain Factor of Safety

    Homework Statement Hello, I've been given a question: The ultimate strength of a round steel rod is 560MPa. If a factor of safety is 6 is required, what is the maximum permissible load for the rod if it has a diameter of 6.9cm? If anyone can explain how to set up this...
  49. J

    Do strain gauges need calibration

    do strain gauges need calibration
  50. S

    Learn How 6 is Derived in Strain Gage Bending Formula

    In strength of materials, we have to do a project using strain gages to measure a weight between 0 and 10 lbs with an accuracy of .1lbs. My group is using bending strain. We have a formula, S_{}b=\frac{F*L*6}{E*b*h}, where F is the weight applied, L is the length, E is the Young's Modulus, b...
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