Strain Definition and 462 Threads

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. C

    Structures and Materials problem - stress and strain

    Homework Statement A 4000 kg car traveling at 160 km/h crashes into a concrete post. If all the kinetic energy of the car is used to crush the low alloy steel at the front of the car, how many kg of steel will be crushed before the car stops? Properties of low alloy steel from a table of...
  2. P

    How Does Strain Affect Triangle Geometry in Tensor Analysis?

    Homework Statement Strain tensor E = [0.02 0 0; 0 0.01 0; 0 0 0.03] (no shear strains). A triangle consists of points A, B, and C, each on axis X1, X2, and X3 respectively. The lengths OA = OB = OC, and D is the midpoint of AC. The direction cosines of AC are (1/sqrt(2), 0, -1/sqrt(2)) and...
  3. A

    Strain Calcs: Convert mm/cm to m?

    Ok, an easy one I think? I am given an equation to work out the strain on a beam, the dimensions of the beam are in the equation (obviously) and in the question these are given in mm and cm, am I right in thinking all the measurements in the equation need to be in m and the question is trying to...
  4. A

    Stress strain and tensile strength diagram

    why does stress decrease after it reaches its maximum tensile strength after its plastic range ?
  5. W

    Determine the amount of elastic strain induced.

    [b]A steel alloy specimen having a rectangular cross section of dimensions 18.8 mm × 3.2 mm (0.7402 in. × 0.1260 in.) has the stress-strain behavior shown in the Figure. If this specimen is subjected to a tensile force of 108900 N (24480 lbf) then (a) Determine the amount of elastic strain...
  6. T

    Calculating the Tensile Strain of a Glass Rod

    Homework Statement If a glass rod of diameter 1cm is loaded with a 1kN tensile load and has a young's modulus of 70 GPa, what is the tensile strain? Homework Equations The Attempt at a Solution Im sure if somebody could tell me the formula for this i could work it out easily
  7. J

    How Do You Calculate Strain in a Faulty T-Delta Rosette Configuration?

    Homework Statement For experimental validation of a design based on FEA, a prototype was tested using strain gauge rosettes at critical locations in a typical t-delta configurations, consisting of 3 gauges: A, B, C and fourth (extra) gauge D. D normally serves as a check on the strains recorded...
  8. H

    Is the Last Term of the Infinitesimal Strain Tensor Correct?

    I read that http://img196.imageshack.us/img196/1705/71301190.png I am not so sure about the last term. Shouldn't it be http://img10.imageshack.us/img10/3962/88484785.png instead?
  9. G

    Stress and Strain, simple question Just need a clarification

    Homework Statement A tow truck is pulling a car out of a ditch by means of a steel cable that is 9.1 m long? and has a radius of 0.50 cm .when the car just begins to ,move , the tension in the cable is 980 N. how much has the cable stretched? Y steel= 2.0 x 10¹¹ N m² Homework...
  10. E

    How to Calculate Work Done in Extending a Material to Breaking Point?

    Homework Statement A material has a stress of 60,000Pa and a strain of 0.4 at breaking point. Given that it is in the shape of a 2m long cylinder of radius 20cm, what work had to be done to extend the material to the point of fracture? Homework Equations Well i thought work done was...
  11. X

    Understanding strain in stiffness matrix

    Homework Statement node1 node2 O---------------------------------------O a rod with 2 nodes: x1=axial force at node1 x2=axial force at node2 u1,axial deflection at node1 u2,axial deflection at node2 l=elements length E=young's modulus...
  12. P

    Calculate Strain Components: Given Stress Components & E, Poisson Ratio

    My Homework question is The stress components at a point are given by (image attached) units are in "Mpa (Mega pascal). calculate the strain components. Assume E= 200GPa and poisson ratio= 0.25. please guide me. formula to be used? thanks,
  13. A

    Strain gauge - determination of x and y strains

    Homework Statement Determine x and y strains in order to construct a Mohr's circle of strain. A 2-gauge Wheatstone (the third/middle gauge was not working), with gauges 90-degrees apart, was attached to a specimen steel plate 15-degrees offset from the x and y axes. An axial load was applied...
  14. O

    Calculate Tensile Stress with Strain Gauge

    A strain gauge has a unstrained resistance of 120 ohms, gauge factor of 2.0 is connected to steel girder so it experieces tensile stress. If strained resistance of gauge is 120.13 ohm. How do i calculate the tensile stress value? I have looked all over the internet for equations relating but...
  15. O

    Calculating Tensile Stress Using a Strain Gauge

    A strain gauge has a unstrained resistance of 120 ohms, gauge factor of 2.0 is connected to steel girder so it experieces tensile stress. If strained resistance of gauge is 120.13 ohm. How do i calculate the tensile stress value?
  16. S

    Help in strain energy calculation

    Homework Statement When a spring fixed at one end is pulled by a force of 8N, the extension is 40mm. Two such springs are joined in series and is pulled to produce a total extension of 40mm. What is the strain energy in the springs.Homework Equations strain energy, U = Fe / 2 or...
  17. C

    Understanding Half Bridge Strain Values

    Hi, I am using a half bridge strain gage configuration on a simply supported beam. If i get negative strain, does that mean I am getting a positive force or a negative force on the beam? I am confused since one gage is in tension and the other is in compression. Thanks
  18. F

    How to convert force displacement curve to stress strain curve

    Hi i need help with this conversion as i am unsure how to approach this. I have obtained a force vs displacement curve from a Hounsfield materials testing machine, and would like to know how to convert this to a stress vs strain curve. Thanks
  19. P

    Calculate Strain of a Cable: 10-m Long w/ 25-N Sign

    A 10-m long cable has a "No Hippos in the Pool" sign weighing 25-N suspended from the middle of the cable. The cable stretches by 2.5 cm. What is the strain in the cable? I know strain is ΔL/L0, but don't really know how that plays out in this scenario. If you could give me the first step or...
  20. C

    Will our strain gauge accurately measure small forces on a baseball?

    Hi, my group and I are doing an experiment on forces experienced on a baseball. Our setup involves the baseball attached to a motor, which is coupled to a cantilever beam (1/2 inch thick, 7 inch long aluminum rod). The beam has a strain gauge attached to it and we are recording data with...
  21. Saladsamurai

    Stress Strain Problem: Finding the Final Length

    HELP! Stress Strain Question Homework Statement In part (a) of the problem, we found that due to a certain stress, the amount of elastic strain that a material undergoes is \epsilon_E=.0087 and the amount of plastic strain is \epsilon_{pl}=.0113. The total strain is therefore...
  22. M

    Strain: What is the Difference Between h/a and h/R?

    In class we discussed a force exerted on a soft ball against a rigid surface. We were told that the strain (of the order: we are doing dimensional analysis) h/a where h is the height difference from the undeformed ball, and a is the radius of the circle intersection of the ball with the surface...
  23. N

    How Can I Calculate the Strain in the XY Plane of a Thick-Walled Cylinder?

    I have an infinitely long thick walled cylinder (steel casing). I have three strain gauges measuring strain along the length axis(z axis); the gauges are equally spaced. The gauges are on the outside of the cylinder. How can I calculate the strain in the xy plane (cylinder cross section)...
  24. W

    MATLAB Plotting Components of Strain EXX,EYY,EXY in MATLAB

    I am trying to plot the components of the strain EXX,EYY and EXY in a 2D framework in MATLAB. The tensor matrix i have is B[exx,exy;exy,eyy]with each component 32x32 array. The values of Eyy is zero does that mean that there is no strain in the y direction between the two entitie sthat I am...
  25. Y

    Strain of material w. (111) orientation is asymmetric about center point? Why?

    strain of material w. (111) orientation is asymmetric about center point? Why?? My calculation shows an asymmetric strain distribution in InAs/GaAs(111) heterostructure while it is symmetric in InAs/GaAs(001). Someone could give explanation on it??
  26. Cyrus

    Strain Gauge Tutorial: Selection & Tradeoffs

    This is a very good little tutorial on how to use strain gauges and the tradeoffs found by using different sizes. http://www.abacus.co.uk/jkcm/cache/fl0008816.jpg http://signalprocessing.prosig.com/FatigueTesting/strain-gauge-close.jpg[/URL]...
  27. J

    Effect of High Strain Rate on strength of Metal

    What is the main reason for changing the strength of metals under very high strain rate? Do all metals show the similar trend in increased strength under high strain rate? What is the effect of crystal structure on this phenomenon?:!)
  28. J

    Load, elasticity, strain, strength

    Homework Statement A continuous and aligned glass reinforced composite consists of 40 volume % of glass fibers, having modulus of elasticity = 10 X 10^6 psi and 60 volume % of polyester resin that when hardened, displays a modulus of elasticity = 5 X 10^5 psi. a) compute modulus of elasticity...
  29. D

    Stress and strain in crystal structures

    Are there stress and strain graphs for different crystal structures?
  30. J

    Calculating Rope Strain for 90' Tree Cut

    I have to cut a tree down that is 90' tall and weighs 12000 lbs. It is leaning 10 deg from vertical away from the direction of pull. My rope is tied at 50' up on the tree and the angle from horiz for the pull rope is 15 deg. I would like to how much strain will be on the rope as I cut the tree...
  31. D

    Effective Strain Calculation for MEng Materials

    Hi, I need some help here. I'm an MEng Materials with no full background in engineering. So I'm in a bit over my head. I'm trying to understand the concept of hydrostatic stresses and effective strain in connection to worn surfaces. I am told I just need to know the equations but then I'm...
  32. A

    How Much Ethanol Can Be Added to a Pressurized Tank?

    Homework Statement A moonshiner produces pure ethanol (ethyl alcohol) late at night and stores it in a stainless steel tank in the form of a cylinder 0.290 m in diameter with a tight-fitting piston at the top. The total volume of the tank is 275 L(0.250 m3) . In an attempt to squeeze a little...
  33. V

    What is the difference between strain rate and velocity gradient?

    What is the difference between strain rate and velocity gradient of a Newtonian fluid?
  34. A

    How Is Displacement Calculated in a Shear Strain Scenario?

    Homework Statement A square steel plate is 10.0cm on a side and 0.500cm thick. Find the shear strain that results if a force of magnitude 9.0*10^5 is applied to each of the four sides, parallel to the side. I found the shear strain to be 2.4*10^-2 Find the displacement x in...
  35. V

    Calculating Shear Strain in 3 Dimensions

    http://folk.ntnu.no/stoylen/strainrate/mathemathics/ This page shows how to find shear strain in three dimensions. I understand how they found the shear strains as x and y components from dividing the change in length by the original length. But from the line "From the figure, it is...
  36. Z

    Calculate Stress & Strain of Marble Column - 1.5m^2, 2.5x10^4kg

    A marble column of cross-sectional area 1.5 m^2 supports a mass of 2.5×10^4 kg. What is the stress within the column? What is the strain? I have already found the stress in the column by taking (25000kgx9.8 m/s^2)/1.5m^2 The problem is i have no clue how to find the strain given...
  37. B

    Bending of Beams - Deflection - Stress - Strain

    Homework Statement A beam of lengh is supported in a clamp system. distance between clamp is 1m. Loads applied at 250mm and 750mm. strain gauge fitted at 175mm with 100ohm resistance. Weight is applied at points a and b. Homework Equations Dont know? The Attempt at a Solution I...
  38. B

    Troubleshooting Mass Measurement Experiment w/ Strain Gauge Sensor

    imdoin an experiment with a strain gauge sensor to measure mass. the 2 strain gauges are in a wheatstone bridge and the wheatstone bridge is connected to 3 741 op amps to amplify the signal. i need an output of cetain voltages for certain masses input. My circuit is giving an output to high...
  39. G

    Can Aether Theory Explain the Field of an Infinite Plane of Charges?

    as I understand it aether theory claims that fields are strain in an elastic medium. the elastic medium can be thought of as a system of springs and masses. (note that the springs store energy proportional to the square of their change in length) I can see how this probably works fine for...
  40. M

    What's the physical meaning of true shear strain and simple shear strain

    :smile:Hey guys. I just get some information about true shear strain and simple shear strain from the lecture of engineering mechanic material .And i just want to know the physical meaning of true shear strain and simple shear strain.As a result, i have found some reference books ,but i still...
  41. Y

    Can someone me with a stress strain graph.

    all the question says is sketch a typical stress strain curve from mild steel and find the following points: yeild strength, young modulus and tensile strength. wtf am i supposed to do?
  42. H

    Strain energy for circular plates

    I need to calculate the strain energy for a clamped circular plate by the governing equation in polar coordinates.. Load is distributed uniformly over the entire area.. And displacement is in transversal direction to the plate,.. please do help me...
  43. H

    Calculating Strain Energy of Circular Clamped Plate

    I need to calculate the strain energy of a symmetrical circular clamped plate using the equillibrium equation in polar coordinates.. Can somebody help me with the method??
  44. F

    OCR Physics AS Level - Strain gauge, temperature, resistance

    I have an assignment in which I have to design a laboratory experiment (not real, only in theory i.e. planning) to investigate how the resistance of a strain gauge attached to a piece of wood varies with the temperature of the wood. *IMPORTANT* My teacher said keep it simple, do not over...
  45. J

    Quarter- bridge strain gauge circuit

    Could anybody help me please? :cry If I have quarter- bridge strain gauge circuit, where strain gauge will have its initial resistance and i will add another 3 resistors, 1 on the same side like strain gauge, and another 2 on the opposite side, so I will balance circuit and my voltmeter...
  46. A

    Estimating Bullet Terminal Velocity from Fracture Energy of Tempered Glass

    1. The question This question is about the design of a car seat belt. The seat belt restraints a passenger when the car is involved in an accident. Use definitions of stress and strain to show that stress x strain has the same units as energy stored per unit volume of seat belt.Homework...
  47. B

    Strain gauge to measure wood expanasivity.

    Hi! Im measuring how much wood expands in different temperatures using a strain gauge. do i need to use a wheatstone bridge circuit schematic? or else how do i heat up the wood without spoiling the strain gauge. Actually how will i heat up the wood anyway? Also how would i draw a diagram to...
  48. F

    Does the resistance of strain gauge increase when temperature increases?

    Hello, could someone help on this question?? ok, I'm trying to find out how much a piece of wood expands and contracts with changes in humidity and temperature, I'm sticking a strain gauge on the wood to detect the expansion and contraction of it. my question is if the temperature increase...
  49. B

    Solving Strain Gauge Problem: Young's Modulus Calculation

    Homework Statement In a bridge circuit R1 is bonded to a cylindrical specimen of diameter 25.08mm. R4 is 160.1ohm, R3 is 2502.7ohm and R2 at balance is 2505.8ohm when the specimen is unloaded and 2511.7ohm when it is loaded with 50kN. the gauge factor of the strain gauges was 2.10. determine...
  50. B

    Mentor.com - What is 'Drift' in Strain Gauges?

    when talking about strain gauges, what does 'drift' refer to exactly?
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