Stress Definition and 1000 Threads

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...

Homework Statement A long, hollow, thick elastic cylinder (E , v) is surrounded by a thin elastic band of thickness t made of a different material (E_2 , v_2). The fit is ideal, such that neither a gap nor a pressure exists. An internal pressure p is then applied at the inside radius (r=a) of...

Hi, I am having trouble understanding why Tij can be non-zero for i≠j. Tij is the flux of the i-th component of momentum across a surface of constant xj. Isn't the i-th component of momentum tangent to the surface of constant xj and therefore its flux across that surface zero? What am I...

Homework Statement A cable containing 37 strands of 0.0250" diameter steel wire successfully supports 1000 lb load in tension. Calculate tensile stress? Do you think this is a reasonable and safe design stress level?Homework Equations tensile stress = F/A The Attempt at a Solution A = [...

Analysis of scoop stretcher -- deflection and bending stress help I wanted to do a theoritical force analysis on the scooping part of scoop stretcher (a tapered rectangular plate). Can anyone suggest how to determine its deflection and bending stress ?

Homework Statement The force on a knee cartilage can cause a large force to deform it. The cartilage area is 11cm^2 and the shear modulus is 12MPa. Max force at impact is 904N at an angle of 12 degrees with the cartilage, through what angle (in degrees) will the cartilage be deformed...

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...

Homework Statement Hello I'm trying to self study A First Course in General Relativity (2E) by Schutz and I've come across a problem that I need some advice on. Here it is: Use the identity Tμ\nu,\nu=0 to prove the following results for a bounded system (ie. a system for which Tμ\nu=0...

(this is not a hw) Assume you have a magnet of dimensions x_m, h_m, remanent flux density Br, and coercive field density Hc. The magnet is placed in a magnetic "C" structure (perfect iron) such that it is connected on one side but there is an airgap on the other side. xxxxxxxx xx... xx...

Hello, Hi There I am trying to obtain the relations of the conserved charges of the stress tensor, it has 4, one is the hamiltonian and the other three are the momentum components. \vec{P}=-\int d^3y \sum_i{(-\pi_i(y) \nabla \phi_i(y))} And i have to prove the conmutators...

Hi, I am looking to use My/I to find the maximum bending stress for a beam My problem is I don't know how to find the bending moment- the reason why: The beam has more than one point of load, aside from the reaction points. (Pin joint cantilever beam) The sum of all moments equal 0...

I don't really understand why use proof of stress. One reason I can come up with is: For materials without a clear distinct yield point, yield strength is stated as stress at which permanent deformation of 0.2% of original dimension will result. (a dictionary definition) Other than that...

Homework Statement Stuck on two similar problems: "State the normal stress boundary condition at an interface x_3-h(x_1,x_2,t)=0between an invisicid incompressible fluid and a vacuum. You may assume that the interface has a constant tension." The second question in the same but the fluid is...

[b]1. I need to know the stress σ in the "y" direction. [b]2. I will use σ=P/A equation. [b]3. First (-2*10^6)N*0.4m=-0.8*10^6N Then σ=P/A=(-0.8*10^6N)/(0.4m*0.02m)=-100*10^6Pa. Is this corrects?

This paper discusses the Bell spaceship paradox: Petkov, "Accelerating spaceships paradox and physical meaning of length contraction," http://arxiv.org/abs/0903.5128 PF has a FAQ on this paradox: https://www.physicsforums.com/showthread.php?t=742729 My purpose in creating this thread is *not*...

Hello Everyone I'm trying to get a deeper understand about this, and I hope you guys can shed some light on the issue. I'm not an enginner, so this may sound a little dumb. Anyway, here it goes. Suposse I drop a piece of chalk. As it hits the floor, it will likely break into pieces, and...

Given the stress tensor in a point, determine the zero normal stress plane. ...2 3 0 T= 3 2 0 ...0 0 5 ---------------------- Eigenvalues: σ1=σ2=5, σ3=-1 It must be simple, but I don't know how to determine the normal vector of that plane analytically. I know σ=0. t=Tn=σ+τ=τ If normal stress...

I've been working on Ex 5.4 in MTW. The maths is fairly straight forward, but I don't really understand what is going on! In part (b) what are the 'forces' pushing the volume through a distance? If they are forces, they must produce an acceleration but we have a constant velocity. Are these...

I'm trying my first design and want to make it successful before I actually make the product. I want to calculate what the stresses are and where they are likely to be. F is a varied load from -10 to 10 kN To find the critical points, should I check the points that i labeled A, B , C ...

Could someone help Please? I am trying to mount a driveshaft to an electric motor for a Segway project and determine the required bolt size to prevent failure. The Segway must be able to carry 120kg and is powered by two electric motors. The drive shaft has a diameter of ø12mm and is 91.6mm...

http://www.glassalchemy.com/media/upload/image/stressfig1.gif In the manufacturing of glass(flat glass),the outside cools first followed by the inside.So,this means that the outer surfaces compresses on the hot inner surface.What I don't understand is how the tensile stresses are developed on...

Can someone link a website or attach a picture of a chart distinguishing the differences between the stress risers in a shear pin (round circular shaft) with a V-notch groove versus if it was a rounded groove. I have been looking but can only find charts, tables and graphs for round circular...

I am trying to understand stresses that are induced by thermal gradients. Now, I can think of a hundred different questions to ask, but I want to take baby steps to get there. Let's just talk about a simple cantilever beam in the x-y plane where the x-axis is the beam's longitudinal axis and...

I'm doing a survey on the topic of "gas turbine blades stress analysis" to see what areas are not focused on in this subject. I've found that not many people talk about the aerodynamic forces on the blade. Am I missing something, are they included in the calculation or are they too small to...

I have a question about the Von Mises Stress Ellipse: http://upload.wikimedia.org/wikipedia/commons/4/48/Tresca_stress_2D.png I understand that this equation if a component is subject to more than just an axial stress, the effect must be account for. I also understand that the ellipse is...

Problem statement: Two 3/4-in.-diameter nylon rods are spliced together by gluing a 2-in. section of plastic pipe over the rod ends, as shown in the figure. If a tensile force of P = 500 lb is applied to the spliced nylon rod, what is the average shear stress in the glue going between the pipe...

Problem statement: Two 3/4-in.-diameter nylon rods are spliced together by gluing a 2-in. section of plastic pipe over the rod ends, as shown in the figure. If a tensile force of P = 500 lb is applied to the spliced nylon rod, what is the average shear stress in the glue going between the pipe...

hey pf! in reading a book on viscous stresses i found the following: \tau_{ij}=2\mu\Big(s_{ij}-\frac{1}{3}s_{kk}\delta_{ij}\Big) where einstein summation is used. now we have s_{ij}=\frac{1}{2}\Big(\frac{\partial u_i}{\partial x_j}+\frac{\partial u_j}{\partial x_i}\Big) and then the claim is...

Homework Statement Hi, I am not sure if this is the right place for my question but here goes! The stress tensor in the Si coordinate system is given below: σ’ij = {{-500, 0, 30}, {0, -400, 0}, {30, 0, 200}} MPa Calculate the stress tensor in the L coordinate system if: cos-1a33=45°, and...

In the case of swarms of particles, the stress energy tensor can be derived by considering the flow of energy and momentum "carried" by the particles along their worldlines. Is there a way to interpret the field definition of the stress energy tensor from Wald, p455 E.1.26 T_{ab} \propto...

"Determine working stress and greatest allowable load" Homework Statement The maximum load in a tensile test on a mild steel specimen of diameter 12.5 mm is 95 kN, calculate the ultimate tensile stress. Also, determine the working stress and greatest allowable load on a rod of the same...

I need to find a suitable mathematical method of calculating the stresses at multiple points of a circular ring subjected to point loading. I'll calculate the rest myself- any suggestions?

Homework Statement I am self-studying this note and I am stuck in the derivation of the normal shear stress. I can't see how the relations (23) and (24) come about, i.e. I don't understand \tau'_{xx} = \frac{\tau_{xx}+\tau_{yy}}{2}+\tau_{yx} and \tau'_{yy} =...

Hi, I am trying to model a simple plane stress problem using Ansys. I am using Ansys 14.0. The problem is a simple square plate, without a corner, and with a hexagon hole around the midle. The boundary conditions consist of a constant pressure on the top side, and full constrain on the...

A concrete column having a modulus of elasticity of 20GN/m2 is reinforced by two steel bars of 25mm diameter having modulus of 200GN/m2. Calculate the dimensions of a square section strut if the stress in the concrete is not to exceed 7MN/m2 and the load is to be 400KN. σ in conctete not...

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...

what is shear stress?what is its direction?

Hello, I am having confusion when calculating the first moment of area, Q, to solve for the shearing stress at point a in 13.9, I use the area which is above the point, but for 13.28 its to the right of the point. It seems they are both subjected to a vertical shear, so I don't think that has...

A solid shaft 100mm diameter which transmits 75kw at 150 rev/min. the question is asking me to find the max shear stress and angle of twist per metre of the shaft length. G=80GN/m^2 I was under the impression to find the angle of twist you needed the length in the first place. None of...

Homework Statement An element is taken from the wall end of the cantilever beam that is loaded as per the diagram. What are the stress components of the element, taken at x=0, y=h/2, z=0 Homework Equations σ=My/IThe Attempt at a Solution So from the shear moment diagram, the moment and shear...

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?

Hi guys, I have been wondering if its possible to alter equilibrium concentrations without adding stress to the system? Thanks, Larry

We solved a problem today in class calculating stress in a compound tube. I haven't posted the full question because I don't think I need to. There are two areas that I am not sure how we found them, EX 1: -60*10^6 how does 10^-6 and 10^9 become 10^6 and Ex2: 6.7*10^-5 and here how...

Homework Statement DIAGRAM ATTACHED AT BOTTOM Q. The following statements are true for an element in plane stress state. (this is 2D) (1) one of the principle stresses is 40Mpa; (2) σx= -2τxy; (the algebraic values) (3) in x'oy' with θ=30°, the two normal stresses σx'=σy' Determine...

Homework Statement An L-shaped beam is loaded by a bending moment M under an angle ψ with the horizontal axis. M = 200 Nm and ψ = 45°. Determine the maximum tensile stress in the beam and its location(s). I added the purple moment-vectors myself, they are the horizontal and vertical...

Should it be added to the Cauchy stress to calculate a "total stress", or it doesn't have such a physical interpretation as a surface force(EM field force is usually considered more of a "body force")? Certainly when the MST was first derived before aether theories were made superfluous by...

I am familiar with the formula for energy density: \frac{1}{2} * \frac{Force*Extension}{Area*length} and also the formula for elastic potential energy: \frac{1}{2} * Force*Extension. I noticed that there is a 1/2 in both formulas because we are concerned with the average force in each case...

Could anyone explain the method of finding the circumferencial and longitudinal stress for thick cylinders?

Hello all, I am confused on how to calculate the maximum bending stress in an I-beam. I found the maximum deflection in each beam where the load is placed at the center of the span. I also know all the cross-sectional dimensions of the I-beam. Is it now possible to calculate it? Thanks

Homework Statement 1. Take dimensions of the beam (B, D, web and flange thickness, L) – T- cross section 2. Take the beam span geometry and material properties from the instrument 3. Ensure the beam and load cell are properly aligned and apply a positive (downward) preload to the beam of...