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.
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...
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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...
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...
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.
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...
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...
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?
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...
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...
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...
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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...
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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...
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...
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...
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...
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?
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...
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...
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...
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 $$ σ...
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Our homework is done through mcgraw hill connect. I am able to see the solution to the problem and it contradicts what the book and powerpoint says.
according to the powerpoint given by my professor, moors circle, sigma1 = Sy or yield strength. Powerpoint also states that sigma(x) is...
I am reading a journal article from Balduzzi about shear stress recover on tapered beams. I can not get the exact constants he gets and I am stumped. Above is solving for differential piece of the beam. Equations 16-18 are the ones I am trying to calculate. I attached my work and the...
I have to discuss the Bending moment and shear forces in cantilever and encastré beams. Does anybody know of good websites showing that is simple to understand showing. All i can find is how to calculate and bending moments and shear force digrams which don't really understand.
Can...
A cantilever beam 2 meter in length, 5KN act at point (A) of the beam. There is point x it looks like half way along the beam. how do i workout the distance of point X so work out the magnidues of Ra and Rb so i can go onto working out bending motion and shear force?ruff idea i had
1) Ra x 2...
I had found the singuarity function for the shear and moment. I have a hard time calculating the singuarity function and graphing it using excel. Can anyone explain how to calculate singuarity function and graphing it using excel?
Many thanks for your help
Hi,
the formula for average shear stress in cross-section due to bending is simple: $$\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...
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...
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...
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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...
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...
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...
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.
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...
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
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...
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...
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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...
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...
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...
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...
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...
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...
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...
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...
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...