Stress Definition and 1000 Threads

Hello everyone, I came across this in J. Anderson's book "Fundamentals of Aerodynamics". "For the type of gases and liquids of interest in aerodynamic applications, the value of the shear stress at a point on a streamline is proportional to the spatial rate of change of velocity normal to the...

Homework Statement When an element of material is subjected to pure shear stress , equlibrium requires that equal shear stress must be developed on four faces of an element . Homework EquationsThe Attempt at a Solution I can't understand the statement . I assume the 'element ' is cubic ...

Homework Statement In my book , the author stated that working stress is the maximum stress premitted under design load . Whereas the allowable stress is given by below ( refer to the notes attached ) http://imgur.com/a/YnimQ Homework EquationsThe Attempt at a Solution So , the working stress...

Homework Statement here's the question , Part of solution was given , but not the final ans . I have tried to do , but i need someone to verify my ans . Homework EquationsThe Attempt at a Solution Since , stress of steel is 12.5 times of stress of concrete . The max allowable stress in steel...

Hi guys, I'm trying to work out the following: Assume uniform shear stress distribution across "Key" width. What is the shear stress (psi) on the "Key" at the interface with the "Shaft"? Torque (in-lb) = 4959 Shaft diameter (in) = 2 Key width/height (in) = 0.3 Key length (in) = 2

Hi, I'm trying to calculate bending stress for a cylindrical beam. I'd like to have my result double checked because I got an answer that doesn't make sense to me. All of this is personal research, so I'm not very confident in my answer. It's a cantilever beam with a point mass of 347.4 oz. on...

Homework Statement For σBC end , i don't understand how the author get (20mm)(40mm-25mm) = 300x10^-6 (m^2) ... Homework EquationsThe Attempt at a Solution IMO, , the area should be the circled part (thin rectangular part of the rod) , but i only know one dimension only , which is 40mm , i don't...

Homework Statement http://holland.pk/uptow/i4/4af070d190cc175e6ca5d326cd60cda2.png The attempt at a solution the question have a possible solution? that equation is based on stress is constant, so how to use this equation to proof? i m a year 2 student. i can only solve part i...

Homework Statement my notes gave that in a 3d cubic , plane stress is state of stress in which two surfaces are free of stress ... Homework EquationsThe Attempt at a Solution Does it mean the we only consider the stresses in xy plane only ? because the object is too thin, so we assume it's 2...

If a large cloud of dust of constant ρ is moving with a given ##\vec v ## in some frame, then at any given time and position inside the cloud there should not be no net energy or i-momentum flow on any surface of constant ##x^i ## (i=1,2,3) because the particles coming in cancels those going out...

Homework Statement https://en.wikipedia.org/wiki/Cauchy_stress_tensor[/B] I don't understand the difference between τxy . τyx , τxz , τzx , τyz , τzy ..What did they mean ? Homework EquationsThe Attempt at a Solution taking τxy and τyx as example , what are the difference between them ? They...

If a rod is in compression, will the minimum area on rod ( the section where there is a hole for pin) stress free? What if the rod is in tension? The rod BC is in compression and the boom AB is in tension? http://imgur.com/a/6asfB

I read on a table by Dr Lynn Fuller on sputtering various materials and there was a table relating RF sputtering power to stress, with a sweet spot at around 300 watts per square inch or roughly 500 milliwatts per square millimeter on the target. The material in question is Silicon Carbide...

Hello everyone, could you help me with this exercise? I am stuck, and I can't find anything on the internet that solves this. Your help is very much appreciated :) 1. Homework Statement Circular steel bar, clamped at extremities. Two parts: A(ab)=800mm² A(bc)=400mm² L(ab)=...

Homework Statement In the question , the author calculated the Ixx and Iyy , but he used the greater value (Ixx) in the calculation to calculate the shear stress , why did he do so ? why the greater value is used ? Homework EquationsThe Attempt at a Solution

Homework Statement I think the notes is wrong . in the notes , it's given that σ allowable > Mmax / Ze Homework EquationsThe Attempt at a Solution i think it should be σ allowable > Mmax < Ze , am i right ? How could the σ allowable > Mmax / Ze ? If σ allowable > Mmax / Ze , the beam will...

If I am using a new material in ansys, let's say I assigned it as solid linear elastic and I assigned density, young's modulus and poisson's ration and then I applied large deformation for this material so that it should be experience non-linearity ...I wonder how Ansys can give the results...

It is one more weekend before I get an official answer for my PhD request... I am totally broken (mentally) and stressed as I am the worst-case-scenario person... In the past, this trait of mine made me reach a point where I said "screw it, if it happens it happens"... unfortunately this time it...

Homework Statement In the in the first image , it's shown that the shear stresses has positive sign, whereas in the second image e (circled blue part) has different sign convention,which is positive and negative, which is correct? Homework EquationsThe Attempt at a Solution IMO, the second...

http://www.efunda.com/formulae/solid_mechanics/mat_mechanics/pressure_vessel.cfmaccording to the text above, we assume that force acting on the thin wall is p*2pi*r^2 whcih is the internal area of vertical slice. But I am not sure why the area has to be 2*pi*r^2. I mean, why pressure on the...

From Carroll (2004) It is possible to derive the Einstein Equations (with ##c=1##) via functional variation of an action $$S=\dfrac{S_H}{16\pi G}+S_M$$ where $$S_H= \int \sqrt{-g}R_{\mu\nu}g^{\mu\nu}d^4 x$$ and ##S_M## is a corresponding action representing matter. We can decompose ##\delta...

Homework Statement in the formula of shear stress τ = (V)(Q) / It , Q=Ay = first moment of inertia of area, the area can be located above(or bottom) at the point of interest) when the chosen point is at the wall(boundary) , why shear stress = 0? Homework EquationsThe Attempt at a Solution When...

I have to calculate Airy's stress function for a cantilever beam made of two different material along its length. The young's modulus of the first half is E1 and E2 for second half. The beam is made such that these materials are joined to each other one after other along its length. At the...

Homework Statement https://en.wikipedia.org/wiki/Bending [/B] form the link, we know that σ represent the bending stress, I'm wondering can I call the bending stress as normal stress act at the cross sectional area of beam?Homework EquationsThe Attempt at a Solution IMO, they are not the...

I have an application where I'm trying to lift an object by using a pulley and pulling on the cable. We were forced to use a pretty small pulley and thin cable, so my question is how to analyze the total stress of the cable? I should be looking for axial stress, bending stress (cable around...

Homework Statement I know that an element that is subjected to max shear stress is 45 degree away from position of an element that is subjected to principal stress.I couldn't understand why the θ s= θ p -45 degree? Cant it be θ s= θ p +45 degree ? Homework EquationsThe Attempt at a Solution...

Homework Statement in the formula of shear stress, t is the width of member's cross sectional area calculated about neutral axis. for τc , why t is 6.4 ? Why not 102.1 ? second question, why we have to consider that specific area? Cant we consider the (red) area? Homework EquationsThe Attempt...

Homework Statement i know that to calculate the shear stress, formula is τ= (V)(Q)/ (I)(t) So, why the author choose to use Ixx, but not Iyy for shear stress at P? Homework EquationsThe Attempt at a Solution IMO, we should done the question in 2 ways, which are by using Ixx and Iyy...

Homework Statement http://ocw.nthu.edu.tw/ocw/upload/8/256/Chapter_7-98.pdf refer to page 3 in the 2nd, 3rd pictures, i have problem of finding σx'Homework EquationsThe Attempt at a Solution why can't use the formula to find σs ? it's given that σx' = ( σx+ σy)(0.5) + (0.5)( σx- σy)cos2θ +...

Homework Statement In my book, I was told that when an element is subjected to pure shear stress, equalibrium required that equal shear stress must be developed on four sides of the element...these stresses must be direct toward or away from opposite corners of element.. Homework EquationsThe...

Homework Statement where V = total shear force at the location in question; Q = statical moment of area; t = thickness in the material perpendicular to the shear; I = Moment of Inertia of the entire cross sectional area. based on this formula , the shear stress is max at the neutral axis of...

Homework Statement in the old thread , i was told that The formula for calculating the shear stress is a beam is ##τ = \frac{V ⋅ Q}{I ⋅ t}## τ - shear stress V - shear force Q - first moment of area above the location where the shear stress is calculated. I - second moment of area for the...

Unsure how to calculate in order to get the stress (N/mm2) and strain (%) if: a material has a length of 50mm diameter of 12mm Load: 11.5 kN Extension 0.025 mm Help on how to work this out would be very appreciated :)

Homework Statement Refer to the second photo , Q= Ay Does the author mean point P is at the center of the region (62.5mm x 100mm) ?The figure is not labelled well i am confused Homework EquationsThe Attempt at a Solution In the notes , I was told that y is the location of the shear stress is...

What effect do stress hormones like cortisol and adrenaline have on the limbic system?

Hi! I am looking for a textbook that explains/describes for moving mechanical structures (such as linkage mechanism, engines, ... and not buildings, bridges, ...) the stresses, deformation, wear, temperature change, ... due to operating. E.g. Linkage mechanism: what are/defines the stresses...

The rate of working of the Reynolds Stress can be written as: where ui is the fluctuating velocity and Ūi is the time-averaged velocity. It is stated in the textbook that, if we integrate the above equation over a closed volume V, the divergence term on the left integrates to zero since τRij...

Hi all, I am currently trying to understand a paper which presents a model for sand production and wellbore collapse in the oil&gas industry. The paper refers to stresses and pressure in "s.g." instead of Pa or other pressure/stress units... values tend to range from 0.4 s.g. for cohesive rock...

Homework Statement a.)why the angle θ p is in clockwise direction? why shouldn't it be in anticlockwise direction? b.) I have labelled A,B ,C and D...Why the maximum normal stress is labelled at location A? while the min stress is labelled at location B? Can I label the min and max stress at...

Homework Statement why the angle of shear stress ( θs) is given by θp - 45 ?? Homework EquationsThe Attempt at a Solution the difference in angle of shear stress and normal stress is90 degree , am i right? why it's negative 45 degree? is it wrong?

Homework Statement can someone explain about part b (tensile stress) here? in which way does the stress act? Homework EquationsThe Attempt at a Solution FromW wikipedia, tensile stress refres to the stress to break a rope...How does it related to the case above?

Hi everyone! I have perhaps a basic question, but I can't dealt with it. I have a rectangular sample 50x150mm of let's say wood. The sample is compressed from the top over the width of 4mm. I know the shortening of the sample at 70 mm from the bottom (from experimental testing) and I know the...

Homework Statement why the shear stress is maximum at the center ? while the normal stress is maximum at the boundary ? Homework EquationsThe Attempt at a Solution why shouldn't the shear stresss maximum at the boundary ? this is because shear stress is to pull the 2 surface apart [/B]

Homework Statement is the circled part wrong ? Homework EquationsThe Attempt at a Solution how could 0.5 sin2theta = ( 1 + cos2theta ) / 2 ?

Hi, I would like say that in this link ( ) and starting from 56.28 Suskind tries to find the energy tensor equation using \phi, afterwards he finds a equation similar to wave equation in terms of \phi. My question is: For what does \phi stand ? I could not capture the meaning of \phi. Could...

I am trying to derive the strain at the base of a cantilever beam with a known deflection. I know the bending stress is equal to Mc/I, so the strain is Mc/IE, where c is the distance from the neutral axis. For a point load ,P, the strain would then be PL/IE. Since the deflection is known I...

Is latex balloon maximum strain independent of latex thickness? I have been in search of a latex balloon that is relatively small when deflated and very large when fully inflated. Standard balloons that reach the desired inflated dimensions are much larger deflated than I would like...

Whether we are using Soderberg or Goodman line; it is two dimensional Cartesian coordinate system in which x-axis is the mean stress and y-axis is stress amplitude. For them to calculate we have two values one is maximum stress and other is minimum; I found on Quora.com that they are not...

All we know the usual stress strain diagram obtained from tensile test from universal testing machine. As modulus of elasticity is material property that means till proportional limit slope will not change. As it is not a force vs elongation curve that means there will be no re-scaling to be...

< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown > Problem Statement: Case 1: Mass is m; Cross sectional area is uniform A. What will be the stress in the middle section. Case 2: Bar is massless; What will be the stress in the middle section...