# Stress Definition and 111 Discussions

In linguistics, and particularly phonology, stress or accent is the relative emphasis or prominence given to a certain syllable in a word or to a certain word in a phrase or sentence. That emphasis is typically caused by such properties as increased loudness and vowel length, full articulation of the vowel, and changes in tone. The terms stress and accent are often used synonymously in that context but are sometimes distinguished. For example, when emphasis is produced through pitch alone, it is called pitch accent, and when produced through length alone, it is called quantitative accent. When caused by a combination of various intensified properties, it is called stress accent or dynamic accent; English uses what is called variable stress accent.
Since stress can be realised through a wide range of phonetic properties, such as loudness, vowel length, and pitch (which are also used for other linguistic functions), it is difficult to define stress solely phonetically.
The stress placed on syllables within words is called word stress. Some languages have fixed stress, meaning that the stress on virtually any multisyllable word falls on a particular syllable, such as the penultimate (e.g. Polish) or the first (e.g. Finnish). Other languages, like English and Russian, have lexical stress, where the position of stress in a word is not predictable in that way but lexically encoded. Sometimes more than one level of stress, such as primary stress and secondary stress, may be identified.
Stress is not necessarily a feature of all languages: some, such as French and Mandarin, are sometimes analyzed as lacking lexical stress entirely.
The stress placed on words within sentences is called sentence stress or prosodic stress. That is one of the three components of prosody, along with rhythm and intonation. It includes phrasal stress (the default emphasis of certain words within phrases or clauses), and contrastive stress (used to highlight an item, a word or part of a word, that is given particular focus).

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1. ### Engineering An issue with these two curved beam homework problems

Hi, good evening/morning/night! I have a problem with this 2 homework problems about curved beams. In both I must calculate the stress at points A and B. My procedure is correct, but for some reason in: First problem - the effort in A is very close to that of the teacher, but the effort in B...
2. ### Stress in rectangular vessel subjected to hydrostatic pressure

Hi, it's not easy to find formulas for stress in rectangular pressure vessels. However, I've found some in a Polish book titled "Podstawy konstrukcji aparatury chemicznej" (Fundamentals of the design of chemical process equipment) by J. Pikon. The problem is that the book provides equations for...
3. ### Corrugated tube (bellow) under axial load

Hi, I'm trying to verify the results of a finite element analysis of a corrugated tube (bellow) subjected to axial load. Here are my analytical calculations based on Roark's Formulas for Stress and Strain (originally the formulas are from the article "On the Theory of Thin Elastic Toroidal...
4. ### Hyperelasticity - Mooney-Rivlin stress equation

Hi, as I've mentioned in this thread, I am looking for analytical solutions for simple loading cases involving hyperelastic materials. It turned out that the literature on rubber part design might actually be a good lead. In a rather old (written in 1989) Polish book "Gumowe elementy sprężyste"...
5. ### Strength of a chain link

Hi, I am interested in the topic of hand calculations of chain link's strength. I am talking about a regular industrial chain with hanging weight. From what I've read, there are 3 potentially possible approaches: - Lame's problem (circular cross-section has to be replaced with equivalent...
6. ### Hertz contact stress with prescribed displacement

Hi, one can easily find formulas for Hertz contact stress in various cases (two spheres, two cylinders and so on) when force is applied to one of the bodies. But how to get the equivalents of those formulas when prescribed displacement is used instead of stress ? For example, I’ve found this...
7. ### Choosing correct steel beam for a span

I have a weight of 30,000 lbs distributed across a span of 100' and supported at the ends. If I have 3 beams to support this load, each beam would then need to hold 10,000 lbs, and with a F.S of 1.6 each beam would need to hold 16,000 lbs. If I assume my max deflection at 1", then I can find the...
8. ### Frame indifference and stress tensor in Newtonian fluids

During lecture today, we were given the constitutive equation for the Newtonian fluids, i.e. ##T= - \pi I + 2 \mu D## where ##D=\frac{L + L^T}{2}## is the symmetric part of the velocity gradient ##L##. Dimensionally speaking, this makes sense to me: indeed the units are the one of a pressure...
9. ### Is a solid cylinder considered thick or thin?

I have a solid cylinder of diameter 40mm and length 14mm and I have used plane stress approximations in my calculations so far. I know for to assume a thin walled cylinder/tube the wall thickness needs to be less than 1/20 of tube or cylinder diameter. However, what I have found so far is that...
10. ### What is the relationship between force lines and the stress tensor field?

Force lines method is used in Solid Mechanics for visualization of internal forces in a deformed body. A force line represents graphically the internal force acting within a body across imaginary internal surfaces. The force lines show the maximal internal forces and their directions. But...
11. ### A basic doubt about stress and strain

While introducing tensile stress, we're shown a bar fixed at a support being subjected to a force in the axial direction at the opposite end. Then, since the bar is in translational equilibrium, we say that internal forces must balance it out, and this internal resistance per unit area is known...
12. ### Biophysics Q: Impact of stiffness (Young's modulus) on stress failure

Hi. I'm a physician trying to understand the micromechanics of lung injury due to overdistension. The basic idea is that overstretching of the plasma membrane of the lung epithelial cell causes "stress failure" --> i.e. plasma membrane rupture --> cell death. The concepts of stress, strain, and...
13. ### Fatigue life of a simple beam

Hi, some time ago I wondered if it's possible to calculate fatigue life (number of cycles to failure) for complex models analytically, based on static FEA results: https://www.physicsforums.com/threads/fatigue-life-hand-calculations-based-on-static-fea-results.994264/ Unfortunately, it seems...
14. ### Capped pressure vessel - strength and stability

Hi, in mechanics of materials books one may easily find fomulas for stress and strain in thin- and thick-walled cylindrical pressure vessels subjected to internal pressure. However, it is assumed that they are open. So what are the formulas for stress and strain in capped vessels (with flat or...
15. ### Stress in a pipe wall

Consider a pipe. The pipe is not crushed by the air pressure because the same air pressure is acting from inside the pipe. But this means that the material of the pipe is being compressed on both sides by some air pressure. So is it correct to say that the through-thickness stress in the pipe...
16. ### I Stresses Caused By Deformation For Bending

Hi. Say you apply a moment on a beam and bend it into an arch. If you take a free body diagram of a section of the beam you would need normal stresses in the radial direction to balance the forces: I have never seen this brought up before though -- is it correct logic? Also, is this sort of...
17. ### Some questions about Friction in fluid flow

I have few conceptual doubts in fluid mechanics. Here is the one I will ask first. I want to understand the force direction acting on the solid liq interface during fluid flow, Let's say a fluid is flowing in a pipe. Now the fluid applies a shear stress at the walls of pipe in the direction of...
18. ### Calculate the maximum vertical point force P that this beam can sustain

A simply-supported steel beam with a vertical point force P is shown in Fig. 2(a). A cross-section of the beam, which is composed of two identical C-shaped members bolted back-to-back, is shown in Fig. 2(b). Both C-shaped members have a uniform thickness of 1 cm. Pairs of bolts are located at a...
19. ### Lines of Stress in a Material

I was initially curious by the fact that streamlines around a circle appear the same as the lines of stress around a hole: I understand that streamlines are the contour lines of the stream function ##\psi## which satisfies the Laplace equation. I was wondering there is a related function for...
20. ### Beams-Bending stress exercise

A chimney has a rectangular cross-section with external dimensions 800 × 600 mm and wall thickness 150 mm. It is 5 m high. The density of the material is 2000 kg/m3. Assuming that the material is elastic, calculate the maximum uniform wind-pressure loading (N/m2) that...
21. ### I Normal Stress

What's really the difference between pressure and normal stress? Also I know pressure acts normal to a surface from the outside Do normal stress acts from inside? I'm reading bird transport phenomena and this is confusing
22. ### How to decide which component is best in terms of stress and deformation?

Summary: In terms of stress, strain & deformation, what is better for a given component. 1) low stress or high stress 2) less strain or large strain 3) less deformation or large deformation? Some dimensional changes were made in an existing component to study how these changes effect the...
23. ### Fluids doubt

what does it mean that fluid cannot sustain a force that is tangential to its surface.which surface fluids's surface or container? and what does it mean it cannot withstand shearing stress.what's shearing stress and what does it mean here.and why exert force only in direction perpendicular to...
24. ### Find the stretch of a steel wire in a static equilibrium problem.

If I can determine the weight of that heavy object placed on the plank, I will be able to determine the stretch of that wire. But, when using the second condition for static equilibrium (torques of the system equal to 0), I always end up with two unknowns, no matter what point of rotation I...
25. ### Help with formulas for calculating pressure

Hi! This is my first post on here. I need to purchase an air cylinder, most likely hydraulic. The cylinder will have a forming die attached on the end and will be used to crimp two small stainless steel tubes together. The crimp will occur at an offset of .004 inches from each end of the tubes...
26. ### Shear stress direction and the velocity gradient

1)In a flowing fluid in laminar fashion we know that it flows in planes which slides over each other, Let's take a fluid element (cylindrical) in a pipe(Radius=R) the resistive force is (stress)(cross section area of cylinder with radius 'r') acting in backward direction, now if I take Flow...
27. ### Angular speed that breaks a spinning body apart with inertial stress

How to find the angular speed, on which a spinning hollow cylindrical body breaks due to inertial stress(force)? I found 2 sources(http://www.roymech.co.uk/Useful_Tables/Cams_Springs/Flywheels.html (last 2 equations) ...
28. ### Thermal Expansion of a Wire Connected To a Rod

Homework Statement Homework Equations ΔL=LαΔT σ=EΔL/L The Attempt at a Solution For part a, I used the coefficient of linear expansion for copper and the change in temperature to find the change in length (0.068%). I thought part b had the same answer. The two are attached, and I would...
29. ### Poisson's Ratio

Homework Statement A titanium disk (with ##E=107 ~GPa##, Poisson's ratio, ##v=0.34##) precisely ##l_0=8~mm## thick by ##d_0=30~mm## diameter is used as a cover plate in a mechanical loading device. If a ##P=20~kN## load is applied to the disk, calculate the resulting dimensions, ##l_{01}## and...
30. ### Stress and Strain tensors in cylindrical coordinates

Homework Statement I am following a textbook "Seismic Wave Propagation in Stratiﬁed Media" by Kennet, I was greeted by the fact that he decided to use cylindrical coordinates to compute the Stress and Strain tensor, so given these two relations, that I believed to be constitutive given an...
31. ### Testing How to stop freezing in exams

Hello there, I am having a problem to solve in exams. I think it's because am freezing but that's just a speculation. I am a physics-math junior and I study really well, solve without looking at solutions and focus and understand the material. Yet whenever I enter an exam I can always solve the...
32. ### Finding a maximum force in a beam type system before failure

Homework Statement See attached photo Homework Equations Stress = F/A Area = pi d^3 / 4 Sum F h = 0, Sum F v = 0, Sum M = 0 The Attempt at a Solution Hey everyone, after reading the question a number of times and not knowing for certain where to start, I figured because the stress and area...
33. ### Shearing when bolts are arranged radially

Hi folks, I'm currently working on a final year project on the design of a plunger pump. The most recent area I have been studying is the loading on different joints in the pump. For a simplified example I have determined the maximum torque load on the crankshaft from the plungers for the...
34. ### Automotive How to Calculate maximum torque a riveted joint can stand

A plate is riveted with a rivet having small rod like projection over the head and the point as shown in drawing.Considering we fix the plate to a vise,and then giving torque to the Rivet Rod;What will be the Maximum Torque the rivet can withstand without getting loosened and how to calculate...
35. ### Other Restoring curiosity

I began to study mathematics in college because I was fascinated by the subject and have a naturally high degree of curiosity for it along with the rest of the sciences--but stress, depression and other factors take away that curiosity as I progress through each semester, leaving me bored...
36. T

### Vertical stress in soil

Homework Statement In this question , i suspect the total vertical stress at the center of the clay is incorrect . Homework Equations The Attempt at a Solution In the figure , we can see that the water table is art 2m below the sand . So , the 2m sand thick should be dry , am i right ? Only...
37. ### Continuum mechanical analogous of Maxwell stress tensor

Maxwell stress tensor ##\bar{\bar{\mathbf{T}}}## in the static case can be used to determine the total force ##\mathbf{f}## acting on a system of charges contanined in the volume bounded by ##S##  \int_{S} \bar{\bar{\mathbf{T}}} \cdot \mathbf n \,\,d S=\mathbf{f}= \frac{d}{dt} \mathbf...
38. M

### Uniaxial press: 1 ram vs 2 rams

Assume to have 2 hydraulic presses for compacting powders with the following designs: Press A has 2 rams that apply force in opposite directions, pointing towards the powders in the middle Press B has 1 ram that applies force in one direction, towards the base of the press My colleagues keep...
39. ### I Stress exerted on a wooden cube dropped on concrete floor

I wonder if it is possible to at least estimate the stress (or the impact force) that the cube in question will experience due to the collision with the concrete floor. Assumptions: 1. The cube is dropped from height h 2. The cube is relatively small, thus we can neglect air resistance...
40. ### By how much is each post compressed?

Homework Statement A large 30000 L aquarium is supported by four wood posts at the corners. Each post has a square 6.00 cm x 6.00 cm cross section and is 90.0 cm tall. Take Y=10^10 for wood Homework Equations ΔL = FL/AY F = ma ρ = m/V The Attempt at a Solution So the total area is 0.06 * 0.06...
41. ### Determine the highest tension stress and the highest compression stress

Homework Statement Determine the highest tension stress and the highest compression stress along the top edge of the intel. Homework Equations stressx = Mx*y / Ix Ztop = Ix / ytop stress (max top) = Mx - Ztop The Attempt at a Solution

I just found that applying an axial load of magnitude σ on both sides of a ductile rod will produce a max in plane shear stress of magnitude σ/2. Why is this? How can there be shear stress if only a normal force is applied?
43. ### Tube Bending Stress

I have ran an FEA simulation on a lever to work out the stress on the part. I have now started doing some hand calculations to validate the software results and am struggling to get the values to match up. I am unsure whether my calculations are wrong, or whether the software is incorrect. The...
44. ### Axial Thrust

I'm in the process of calculating my combined stress on an axle I am designing, I have calculated the bending and torsional stress, however I need to calculate the direct stress in the axle. In order to do this I need to know the axial thrust in my axle, I understand what axial force is but I am...
45. ### FEA Hand Calculation Validation

I have ran an FEA analysis on part screenshot below. I wanted to do some hand calculations to validate the results. What formula should I use to calculate the stress?
46. ### How to calculate stress on a pipe wall

I have a PVC fitting that keeps cracking. The fitting consists of 2 parts. One piece is placed over the end of a flexible PVC ribbed hose, and the other is inserted inside the hose. The 2 parts act as a compression fitting to attach to the end of the hose. The hose typically has an outside...
47. ### How can I show that the bulk modulus is about r^-4?

Homework Statement Using the equations, show the bulk modulus is about r^-4. Homework Equations The Attempt at a Solution Tried to plug Uij but it is not same as U. To be honest, I don't know where to start.
48. ### Usage of Taylor's formula on stress analysis

Moderator Note: Thread moved from forum Atomic, Solid State, Comp. Physic, so no homework template shown. What function do they use Taylor's formula on? And can you show how they derive it? I know how one derives Taylor formula. Thanks! The text i taken from this...
49. ### I Stress as momentum flux

I'm trtying to get a better understanding of the spatial part of the energy-momentum tensor, and although similar questions have been asked here, I think the point I do not fully grasp has not been covered so far. The stress tensor can be considered as "momentum flux density" tensor. If I...
50. ### Static Equilibrium

I have a 3 pulley system statically balanced hanging weights at a determined relative angle (we are taking into account friction). If I change the position of one pulley, angles will remain the same. However, if I have a 4 pulley system, at the same conditions, changing one's position will...