What is Shear: Definition and 621 Discussions

Shear stress, often denoted by τ (Greek: tau), is the component of stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross section. Normal stress, on the other hand, arises from the force vector component perpendicular to the material cross section on which it acts.

View More On Wikipedia.org
  1. salamikorv

    Engineering Shear stress problem: What decides the sign of Tau_V?

    Im so confused on these solutions here for the shear stresses. Why is Tau_V sometimes negative and sometimes positive? Can someone please explain this and maybe illustrate? Here for example. Heres the solution for problem b): Here Tau_V (talking about F_xQ/(Ir) ) is negative, so how im...
  2. Twigg

    A Lame parameter mu = shear modulus derivation (rogue factor of 2)

    Hello, I am trying and failing to derive that the shear modulus ##G## is equal to the Lame parameter ##\mu##. I start with the linear, symmetric, isotropic stress-strain formula: $$\sigma = \lambda \mathrm{tr}(\epsilon) \mathrm{I} + 2\mu \epsilon$$ I then substitute a simple (symmetric) shear...
  3. greg_rack

    Engineering Analyzing Shear & Bending on Idealized Cross Section

    As you can see from the picture, the cross section to analyze is idealized and the boom areas resulting from this are given. For POINT A) all I did was: for determining the shear forces, integrating the shear flows over the sides to compute the vertical and horizontal contribution of each side...
  4. M

    Engineering Calculating the safe load of a glued structure with given shear stress

    I have tried to calculate the safe load with the equation of maximum shear stress, A = 4*6*10^-4, and the given shear stress 5MPa, but I couldn't seem to get the right answer which is 18kN.
  5. greg_rack

    Engineering Calculating shear center for a "skewed" I beam

    Here is the diagram of the cs: As a premise I must say that this topic(shear center and shear flow distributions) is still very hectic in my mind; I aim to clarify it a bit by asking you guys this :) So, in order to identify the SC location, I must compute at what distance a point shear force...
  6. L

    Tensile and shear capacity of metals

    Steel and other metals data sheets and mill specs most commonly quote some tensile strength metric, like Proof, Yield or Ultimate Tensile Stress. Less common is the value for shear strength. Often as rule of thumb the allowable shear stress is taken as half the allowable tensile stress but, when...
  7. Svelte1

    How is the slope of the shear force equal to the negative of the load?

    At any point between A and C the point load is negative (downwards), in the shear force diagram: positive is upwards, so this slope is negative. The equation says the slope should be positive. Is this something to do with shear force sign convention?
  8. mgong21

    I Derivation of Voigt's Shear Modulus

    How did Voigt derive the average shear modulus of an anisotropic material, G=1/5 (A-B+3C), where 3A=c11+c22+c33, 3B=c12+c13+c23, 3C=c44+c55+c66? The original text is published in German about 100 years ago. I looked for other papers explaining this, but none has explained the derivation. They...
  9. D

    Understanding horizontal shear in beam with vertical load

    In an I-beam, the shear flow is usually shown drawn as on the left, not as drawn on the right. I do not understand why. I do understand: The total horizontal shear force must be zero, consistent with statics.This is satisfied in both images. The vertical direction matches the direction of the...
  10. A

    I Water has no shear force but it can be sheared?

    Is it true that water has no shearing force but it can be sheared? If so, would the sides of a glass holding water shear the water?
  11. greg_rack

    Engineering Transverse shear stress calculation in non-slender built up members

    Hi guys, this is an exercise I have been tasked to solve for an assignment. First of explaining you what I have done to solve it using the shear equation, in order to find the maximum shear stress and the shear flow in the juncture, one big question: how is it legal to utilize the shear formula...
  12. N

    Mechanics of materials - shear flow in built up members

    Hello! I am new to mechanics of materials and I am very confused about the problem below. So the shear formula is: tau = VQ/It From the book (Hibbeler) I understand that Q is "y'A', where A' is the cross-sectional area of the segment that is connected to the beam at the juncture where the...
  13. curiousPep

    Hertzian contact pressure & shear stress

    Hello, I am trying to get some intuition about the direction of the shear stress caused by the Hertz contact pressure. Once I exert some pressure downwards on a spherical object the direction of the Hertz pressure will be upwards. However, this case some shear stress to exist, but I can't see...
  14. M

    Engineering Statics project involving shear & moment diagram of a control arm

    Part of a project I am working on (part #3…see description below) is asking us to find the internal loads (shear and moment) and draw the corresponding shear/moment diagrams of the control arm shown below. It’s a little tricky to me, because all of the members associated with these type of...
  15. Moara

    Engineering Maximum normal stress and shear stress

    First, I am trying to find the external reactions in A and B, but I have only one equation relating ##V_A## and ##V_B##, what other relation could I use ? Once I find the reactions, I can find the external moment as well. Then, I may draw the diagram of moments in each cross section and then...
  16. Rob B

    Shear stress damage due to thermal gradient

    I'm trying to use my rudimentary understanding of material physics to understand a simple problem, and am getting stuck - I hope you can help! My idealized case involves a sheet of infinite extent in length and width direction, to which a linear thermal gradient in the depth dimension is...
  17. F

    The true definition of Poynting effect for simple shear

    Consider a simple shear x=kY, y=Y, z=Z. How is Poynting effect defined? If the normal stress along y is 0 but that along x isn't 0, is that also a sort of Poynting effect?
  18. NSNS

    Calculating Shear Stress from Shear Flow for Scientists

    how to calculate shear stress using shear flow
  19. F

    Stress/strain concentration in shear loadings

    A rectangle (plane strain/stress) is sheared on 3 edges (bottom fixed) so that it becomes a parallelogram. In theory this is pure shear and should undergo uniform deformation throughout the domain. The FEA result for this pure shear loading still shows stress/strain concentration on the bottom...
  20. A

    Election of cut placement for Shear flow -- Hibbeler's example

    Hello. I am reading Hibbeler's Mechanics of Materials (ninth edition). Example 7.5 computes shear flow at a segment where there are nails attached to different boards. He chooses a cut like the one shown here: And gets (by symmetry between C and C') the shear flow q computing the first moment...
  21. A

    Shear flow in thin-walled members -- Hibbeler confusion

    Hello: I was reading about thin-walled members under shear force, specifically example 7-7 of Hibbeler's Engineering Mechanics, Mechanics of Materials. First, the fourth Edition: As you can see above. He starts by computing the moment of inertia on the first equation by subtracting a rectangle...
  22. S

    How to find the length when trying to determine the shear

    The sketch that goes with the problem. My attempt at solving the problem: a) to get σ (I think this is called tension in english) we need the force,and we need the area.From the sketch we can see that the area is A = 6*2 and we convert those in m and than set in the formula we should get $$ σ...
  23. L

    Engineering Understanding Shear Stress Theories: Moors Circle & McGraw Hill

    Hello:) Our homework is done through mcgraw hill connect. I am able to see the solution to the problem and it contradicts what the book and powerpoint says. according to the powerpoint given by my professor, moors circle, sigma1 = Sy or yield strength. Powerpoint also states that sigma(x) is...
  24. G

    Shear stress distribution for a tapered beam

    I am reading a journal article from Balduzzi about shear stress recover on tapered beams. I can not get the exact constants he gets and I am stumped. Above is solving for differential piece of the beam. Equations 16-18 are the ones I am trying to calculate. I attached my work and the...
  25. L

    Engineering Cantilever and encastré beams: bending moment and shear force

    I have to discuss the Bending moment and shear forces in cantilever and encastré beams. Does anybody know of good websites showing that is simple to understand showing. All i can find is how to calculate and bending moments and shear force digrams which don't really understand. Can...
  26. L

    Engineering Bending motion and shear force

    A cantilever beam 2 meter in length, 5KN act at point (A) of the beam. There is point x it looks like half way along the beam. how do i workout the distance of point X so work out the magnidues of Ra and Rb so i can go onto working out bending motion and shear force?ruff idea i had 1) Ra x 2...
  27. mingyz0403

    Engineering Graphing Shear and Moment using singuarity function in Excel

    I had found the singuarity function for the shear and moment. I have a hard time calculating the singuarity function and graphing it using excel. Can anyone explain how to calculate singuarity function and graphing it using excel? Many thanks for your help
  28. FEAnalyst

    Maximum shear stress in an assymetric cross-section

    Hi, the formula for average shear stress in cross-section due to bending is simple: $$\tau=\frac{V}{A}$$ There’s also a formula for maximum shear stress in cross-section: $$\tau_{max}=\frac{VQ}{Ib}$$ But, from what I know, this equation is limited to symmetric cross-sections (rectangular, I...
  29. tracker890 Source h

    Asymmetric beam torsion balance with shear flow

    Dear Everyone: Q: Please help me to understand why the torque of external load to the centroid is different from the torque of internal shear flow to the centroid in the asymmetric beam? Attached please refer to the following link for more details. Question version Original version Thank you...
  30. Kushwoho44

    Principal Stresses in a Shear Flow

    Hi, I was thinking about principal stresses and unfortunately this is a bit of a dark spot for me in my education. I understand principal stresses as the stresses that are present when the co-ordinate system is oriented such that there are no shear stresses, and only normal stresses. As such...
  31. B

    Engineering Angle of twist and Shear stress in a shaft

    Hello, I have attempted the question below. I think i have correctly completed the question. Could anyone see if i have gone wrong? As trying to learn this. I am just worried about the units m to mm. Also the answer being correct, 917.6Gpa. I was unsure what units to use on the answer...
  32. B

    Engineering Calculate shear force and bending moments with a UDL and a point load

    Hello, I am looking for some help. I have completed the question below. I will show my answers. My answer: I believe this to be correct. If it is not would appreciate someone letting me know so i can correct. Now i am attempting this question: Could anyone help, or point me in the...
  33. B

    What is the shear stress in a lap joint with a double lap configuration?

    Here is a MCQ which I'm struggling to answer The option with a red dot is the answer I chosen and think is right I know that stress is equal to force/area Area i.e. the cross sectional area of a circle is (pi*d2)/4 Looking at the simple lap joint, force is simple P netwons hence stress is...
  34. ANSAN

    Need the Permissible Stress (Shear & Bending) values of various materials

    Hi all, i need Permissible stress (Shear & Bending) values of various materials that is used for shaft design, as like below. Is there any software or excel sheet. kindly let know.
  35. A

    Shear Force on Bolts mounting gearbox to engine

    Hello, I have designed a gearbox that bolts on to a fixed engine and fixed pump. It is completely supported by them. The total mass of the gearbox and the components attaching it to the engine and pump is 7.7kg. Its centre of mass is 0.167m along the x-axis and 0.09m along the z-axis from the...
  36. archaic

    Finding Shear Strain: Step-by-Step Guide

    $$S=\frac FA\frac hx\Leftrightarrow\frac{F}{SA}=\frac xh=\text{shear strain}\\ \frac xh=\frac{9.0\times10^5}{10.0\times0.500\times10^{-4}\times7.5\times10^{10}}=1.2\times10^{-3}\\ x=1.2\times10^{-3}\times0.500=6.0\times10^{-4}\,cm$$ I'm doing something wrong, any help?
  37. J

    Shear stress, Direct stress and factor of safety -- help please

    hello, I'm new to this forum and I'm looking for some much needed help/guidance as i have absolutely no idea on how to workout my assignment! any help would be much appreciated
  38. E

    Shear and Tensile Strength of Bones

    Hello there, I'm currently studying shear and compression. I am wondering, in my textbook, it says that most bone fractures are not caused by compression but by twisting or bending?? I mean bone's shear modulus is as great as that of a steel's, but its young modulus is far smaller than its...
  39. Carbretta

    Engineering Calculating Shear and Tensile force in a rivet at an angle

    Hi all! I have used this forum a few times and it has been very helpful, however now I am stuck. I have completed the question above however I have conflicting information regarding the Tensile and Shear force being applied to the rivet. I use the following calculation for this: Shear Force...
  40. T

    Understanding Shear Force: How to Calculate and Interpret Shear Force Diagrams

    Hello all I was hoping some could shed some light on the idea of shear force on members. I have the following simply supported beam:- Considering only the left of the beam to just to the right of F1; my gut instinct would be to say that the shear force or failure is greatest at the...
  41. A

    Shear Stress Distribution Along a Beam

    I know that shear stress in horizontal beams has a parabolic distribution, so that the max shear stress occurs at the neutral axis. I also understand that for a beam subject to a distributed load with supports at its ends, the magnitude of the shear force is highest at the left and right ends of...
  42. V

    Shear strength of a cut I-beam

    Hello, I'm in the process of building a 2 story townhome project and had a question on a beam. The structural engineer is calling for a cut I-beam on top foundation which spans over the garage (10') and the load will be placed on just the top flange (see attached). The structure will cantilever...
  43. Zouatine

    The normal and shear stresses

    Hi! i have this exercise and solution : Exercise: steel plate given in figure (a) is joined by an inclined butt weld ,the plate is subjected to tensile stresses in both x and y directions, σ(x)=54 N/mm^2 and σ(y)=38 N/mm^2 , 1) Determine the normal and shear stresses of the butt weld...
  44. M

    Calculating Shear Force between a Moving Film and a Cylinder

    If I have a catheter covered in a thin sheathe (think a cylinder, covered by a thin plastic film), how should I go about calculating the shear force it takes to unsheathe the catheter from the sheath (no torque here, just the catheter moving in and out)? I've thought about strain gauges (but...
  45. vivek_salman

    Shearing / Cutting Force - Rubber bale

    I have been assigned by my tutor to design a hydraulic guillotine (rubber bale cutter). After designing its features of the hydraulic, cutting blade etc. I tried to calculate the force needed of cutting a piece of Rubber bale (Natural as reference) having an ultimate tensile strength of 30 MPa...
  46. I

    How can I calculate the bending moment of a pin in double shear?

    I have attached an Excel-worksheet in which the problem should be clearified. The problem concerns the calculation of the bending moment acting in a pin in double shear, experiencing a certain load from a hydraulic cylinder. The plate thicknesses should be taken into account. Specifications and...
  47. person123

    I Find Frequency of Block Oscillation Due to Shear Force

    Hi. I'm trying to determine the frequency of an block (roughly a rectangular prism) when the oscillation is due to a shear restoring force. Here is a diagram: In the derivation, ##\rho## is the density of the block,##G## is the shear modulus of the block, ##y## is the elevation of the element...
  48. naji0044

    Find an expression for the shear stress of this figure

    Summary: I have trouble to define the y distance in my coordinatesystem I need to find an expression for the shear stress on the I figure, where the green parabola illustrates the function. I made a cut, where I defined the length from the start of figure I to the cut as z1. The formula for...