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. PetePetePete

    Stress and Strain Coursework Question

    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...
  2. S

    Designing a Strain Gauge Load Cell: Q&A on Force Measurement

    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...
  3. S

    Calculating Strain Gauge Grid Line Output: A Step-by-Step Guide

    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
  4. D

    Applied pressure through fluid to measure strain

    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...
  5. Dethrone

    MHB Bridge Question - Stress / Strain

    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...
  6. S

    MHB Explaining the Formula for Beam Strain: Motivating \epsilon

    i am working on the beam theory. where i have to consider a pure bending of a beam. they question asked was i should motivate the formula for strain \epsilon and use a setch to explain. how do i motivate the formula
  7. S

    Stress and Strain: Understanding Axial Loading

    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...
  8. WannabeNewton

    Interpretation of vorticity with non-vanishing strain tensor

    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...
  9. N

    How Can Strain Be Calculated from Force Displacement Data in a Cantilever Beam?

    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...
  10. F

    Strain Gauge Load Cell Questions

    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...
  11. Greg Bernhardt

    Stress and Strain Tensor Basics: Definition, Equations & Moduli

    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...
  12. K

    Minimize Strain Gage Errors: Tips & Solutions

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  13. C

    Transfer function between torque and strain

    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...
  14. E

    Longitudinal strain rate derivation

    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...
  15. L

    Determine the strain rate for a material fiber

    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...
  16. L

    What is the average strain in a steel spike when struck by a 30kg sledge hammer?

    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...
  17. V

    Deformation, stress, and strain problem.

    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...
  18. I

    Understanding Archery Risks: RSI & Eye Strain

    Homework Statement Each year, 5.7% of archers develop repetitive strain injury (RSI) in their arm. Each year, 3.6% of archers develop problems related to eye strain. However, 91.2% of archers develop neither. (a) Formally define sensible event notation, and summarise the information in the...
  19. T

    Strain energy in a tapered rod under torsion

    Homework Statement The Attempt at a Solution http://imgur.com/3ZfjPxM.png So if you look at my attempt, I integrated the strain energy density function and at the end everything cancels out. Does anyone know what I did wrong?
  20. T

    MECH 360 - Question about strain energy problem with beams

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  21. F

    Can the Flexural Strain Formula Determine Strain in a 3 Point Flexural Test?

    I've been tasked with designing an experimental rig for some students and have run into a bit of a cul de sac with this particular issue. Allow me to elaborate: A beam of known geometry (length, depth, width, etc.) is being bent over a hollow cylinder. The beam has holes machined through at...
  22. J

    Strain Energy Release During Fracture -Where does it go?

    When a bolt is pulled in tension and eventually fractures, is all the built up strain energy dissipated in the formation of the new surfaces? Does any energy do into accelerating the broken halves of the bolt? Imagine that two plates are bolted together. As the two plates are forced apart...
  23. T

    How Do You Calculate Lateral Strain from Diameter Changes?

    I'm trying to compute lateral strain for a bar (strain that would make it thicker, or have more cross sectional area). All I know are the initial and final diameters. This gives me d1 and Δd. Would the lateral strain be Δd/d or ΔA/A? (A is area)
  24. A

    ANSYS Workbench: Plane Strain Problem

    I have an assembly of two 2D surfaces. I modeled it on SolidWorks however, I could not import it to Ansys in any format. I tried SLDASM, Step and IGES. I tried modelling the same on Workbench modeller. However, I could not figure out a way to model 2D assemblies on the modeller. Can someone...
  25. anthonyk2013

    Stress and strain compound bar question

    A compound bar is made using stainless steel tube with an aluminium alloy bar positioned concentrically inside it, and rigidly fixed at each end. The cross sectional area of the tube is 400mm^2 and the cross sectional area of the bar is 300mm^2. The combination is in tension and limiting stress...
  26. anthonyk2013

    How Do You Calculate Young's Modulus from Tensile Stress and Strain Data?

    A light alloy bar is observed to increase in length by .35% when subjected to a tenstile stress of 280MN/m^2. Calculate youngs modulus for the material. σ=280MN/M^2 x=.35% ε=? E=? L=? I have too many unknowns where do I start?
  27. ajayguhan

    Expression of bulk modulus of a cube in terms of strain

    In my text it's given when a cube underwents a uniform unit tensile force be applied in all six faces, bulk module=1/3(α-2β) Where α is longitudinal strain and β is lateral strain.is there a derviation for it..? And it states in x direction there will be increase in length and in y, z...
  28. ajayguhan

    What is the reason behind the stress being zero when stretching a rod?

    I know that I'm wrong but couldn't find where I'm Stress=internal force /area When the body is in equilibrium, force applied equals internal force.therefore stress=force applied/area Let us stretch a rod by two equal and opposite force.,say f and -f...thus total force is zero Stress=...
  29. I

    How many columns are needed to support the roof of an underground tunnel?

    Homework Statement A tunnel of length L = 151 m, height H = 7.7 m high, and width 6.2 m (with a flat roof) is to be constructed at distance d = 60 m beneath the ground. The tunnel roof is to be supported entirely by square steel columns, each with a cross-sectional area of 960 cm2. The mass of...
  30. J

    Stress and strain from atomic point of view

    Hi all, This is a question regarding stress and strain. Can someone please explain the concepts of stress and strain in atomic level? My understanding is as follows.Let us consider a metal bar or rod that is subjected to tension.The load applied to the bar will be try to elongate the...
  31. J

    Stress and strain atomic level

    Hi all, This is a question regarding stress and strain. Can someone please explain the concepts of stress and strain in atomic level? My understanding is as follows.Let us consider a metal bar or rod that is subjected to tension.The load applied to the bar will be try to elongate the...
  32. L

    Calculate strain from bending moment?

    Homework Statement Simply supported beam, all values known now I believe as this is the last question on it. I have spent a long time trying to work this out: The bending moment is to be verified using a strain gauge bonded to the outer surface of the beam at the point of max bending...
  33. 1

    The difference between strain and strain_y

    Homework Statement I am doing a lab. My textbook defines strain as ε= lf-lo and E = σ/ε. In my lab, E= σy/εy. εy = ΔLy/lo I do not understand how they can both = ε as lf-lo is completely different from ΔLy/lo. ΔLy is "elongation at yeild" according to my lab. Why are they both labelled E...
  34. M

    What is the relationship between stress and pressure?

    I studied that Stress is defined as Force per unit area. Force here referred to internal force between the particles in the materials per unit area. am i right? Is pressure a kind of stress? (Internal force per unit volume) for fluids but i have studied that pressure is external force per...
  35. E

    Designing an instrument with strain gauges

    I am busy studying engineering and I have a subject that requires us to design and build a working instrument using strain gauges. We have a workshop at our disposal and all necessary materials and electronics. At this moment my group and I are stuck with coming up with an idea for an...
  36. C

    Strain gauge force sensitivity

    Hello, I'm new here and that's because I've run into a problem I can't reliable find anywhere else. I guess I need some personal experience or input from someone. I'm designing a force sensor for a project of mine, it will be measuring force in three orthogonal directions. Now, I'm confident...
  37. U

    Concept question on .2% strain

    Hi all, I am trying to wrap my head around this and for some reason I am blocked. I have taken Solid mechanics and strength of materials and am always used to calculating strain as ε=ΔL/L. I might be missing something easy as it has been a year since the class but in my Manufacturing...
  38. J

    Understanding Stress & Strain in 9th Standard Physics

    Hi all, This is my first post in PF I'm doing my ninth standard in India,My knowledge in physics is limited so please forgive me if I ask something basic Can anyone clearly explain me the relationship stress and strain,because I thought when a material deforms (even to the slightest...
  39. I

    Independency of the frame of reference of the strain rate tensor

    I've got a problem regarding tensors. Premise: we are considering a fluid particle with a velocity \mathbf{u} and a position vector \mathbf{x}; S_{ij} is the strain rate tensor, defined in this way: \displaystyle{S_{ij}=\frac{1}{2}\left(\frac{\partial u_i}{\partial x_j} +\frac{\partial...
  40. S

    Stress strain curve for concrete in Eurocode

    Hello, I am doing simulation using Finite element for the concrete ,this I found the concrete model for the concrete in euro code as attached in the picture. But what I don't understand is basically why the peak of the curve is not the Fck (compressive strength), because the curve maximum is...
  41. B

    Units for Strain? | Learn About Strain & Hooke's Law

    Homework Statement Here is a picture of the problem: http://imgur.com/Ldw1fUF Make sure to click on the picture to make it bigger!Homework Equations The strain/hooke's law equations.The Attempt at a Solution I have this for two parts. The second part is the deformation which I got right. I am...
  42. S

    Need help to verify an attempt to explain strain as point property

    Recently I review some old text and browse around the internet to read about definition of strain and stress. I come across the following document http://web.mit.edu/emech/dontindex-build/full-text/emechbk_4.pdf Previously I have been facing difficulty trying to come out with an...
  43. B

    Quadratic form of strain energy

    Hi, I have some confusion about strain energy. When using Lagrange's equations to derive the EOM of vibrating structures, the strain energy is written as : U = q^{T}Kq ; (q is the vector of generalized coordinates, and K is the stiffness matrix). Writing it in this form makes it easy to...
  44. C

    Calculating the strain in three different ways - experimental error?

    I've recently done an experiment where I've obtained the strain of a channel section beam in bending. I used a strain gauge to get the strain from the midspan and also used dial gauges to get the deflections of the beam under different loading conditions. Along with the readings I've...
  45. G

    Strain on NPT thread in high pressure chamber

    Thanks in advance to any help on this: I am working in a combustion lab and we are designing a high pressure tube reactor. My background is only in math and I have never taken a materials or design course before, so I apologize that this is probably a very basic application and a very...
  46. P

    Calculating Strain in Wood Compression for Plotting Stress

    How can I calculated the wood strain in compression to plot it with stress, if the data that I have is the length and several extension data. The extension data corresponds since the 0 load to the the failure. Thanks. Since the equation for Strain is: ΔLength/Initial Length In order to...
  47. Nemo's

    Calculating Strain Energy in a Hanging Spring

    Homework Statement A spring hangs vertically from a fixed point. When a mass of 94g is suspended from the spring the spring stretches by 2.6 cm before temporarily coming to rest. Determine the extension of the spring at which the strain energy is half its maximum value. Homework Equations...
  48. D

    Strain potential energy and efficiency question

    Homework Statement A sphere of mass 0.1 kg is pushed against a rubber band catapult with a force of 80N, and released upwards. Calculate: A) The strain potential energy when stretched by 0.3m B) The work done by the applied force C) The speed of the sphere when released D) The...
  49. B

    Stress and Strain, load and extension

    Firstly, does a stress vs. strain graph for a material always take the same general shape as its load vs. extension graph (with the same important points, e.g. UTS, having the same shape and corresponding to the same thing)? Secondly, what do the stress-strain and load-extension graphs look...
  50. D

    Strain Hardening vs Colding Rolling

    Do either of these actions impact upon the elastic modulus? I can't think of any reason why they would, but just want to make sure. Thanks.
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