what is a stress concentration? course hero

Stress concentration is the accumulation of stress in a body due to sudden change in its geometry.

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What is stress concentration?

Stress concentration is the accumulation of stress in a body due to sudden change in its geometry. When there is a sudden change in the geometry of the body due to cracks, sharp corners, holes and decrease in the cross section area, then there is an increase in the localised stress near these cracks, sharp corners, holes, ...

How to reduce stress in the body?

There are number of ways to reduce stress concentration in a body and some of these are. 1. Avoiding sharp corners by providing a fillet radius at the sharp corners. By providing the fillet radius at sharp corners, the cross section area decreases gradually instead of suddenly. And this distributes the stress in the body more uniformly.

Why does stress increase in the body?

The stress concentration in a body happens because of the sudden change in the geometry of the body due to cracks, sharp corners, holes, decrease in the cross-section area. Due to these irregularities, there is an increase in the intensity of stress in the body.

What is stress concentration?

A stress concentration is defined as a high localized stress, compared to the average stress of the body, and is typically found in a region that has an abrupt geometric change . This article will walk through the basics of a stress concentration, offer real-world examples to illustrate the concept, and outline methods for reducing stress ...

What is the first image of a stress?

The first image is the original stresses, and the second is the reduced stresses with the larger radius.

Does stiffness mismatch drive stress?

The stiffness mismatch will drive the stress concentration much higher. Don’t assume that the same size radius works for all features. Remember that the stress concentration is based on a ratio, not a magnitude. Don’t place a stress concentration in a high cyclic load if you absolutely must use a sharp corner.

What is Stress Concentration? How to reduce it?

Let’s see how the irregular stress distribution results in stress concentration.

How does a sharp edge reduce stress?

Well, let’s say a sharp edge is experiencing the high-stress concentration, so we can reduce the stress by providing the fillet. As the fillet radius increase, the connection area will also increase results in a reduction in the concentration of stress at these edges. This phenomenon occurs for all kind of stress in the presence ...

What is stress concentration?

Stress Concentration – Definition. Whenever the machine component changes the shape of its cross-section the stress distribution pattern no longer holds good and the neighborhood of the discontinuity is different. The stresses induced in the neighborhood are much higher than the stress induced in the other part of the component.

What is the stress of a member with different cross sections?

It shows that nominal stress in the right and left-hand sides will be uniform but in the region where the cross-section is changing, a redistribution of the force lines within the member must take place. The material near the edges is stressed considerably higher than the average value. The maximum stress occurs at the same point on the fillet and is directed parallel to the boundary at that point.

Why is stress concentration in ductile materials not so serious?

In static loading, stress concentration in ductile materials is not so serious as in brittle materials, because in ductile materials local deformation or yielding takes place which reduces the concentration. In brittle materials, cracks may appear at these local concentrations of stress which will increase the stress over the rest of the section.#N#It is, therefore, necessary that in designing parts of brittle materials such as castings, care should be taken. In order to avoid failure due to stress concentration, fillets at the changes of section must be provided.

Is the sharp bending of a force flow line reduced?

In these three methods, the sharp bending of a force flow line is reduced and it follows a smooth curve.

Which is more suitable for stress concentration study: technical elastic constants or stiffness tensor?

For the stress concentration study, the technical elastic constants are more suitable than the components of the stiffness tensor. The Young moduli Ei, shear moduli Gij, and Poisson ratios νij of a transversely isotropic solid are related to Cij by

How to find the stress of a circular hole?

the stress at the sides of a circular hole is three times the general tensile stress level in the plate , while at top and bottom there is a compressive stress equal to the general stress level. If a crack is thought of, ideally, as a long thin ellipse, the equation above gives some idea of the level of stress concentration at the ends; a crack twenty times as long as its width, for example, lying across the direction of loading would cause a stress, at the ends, forty-one times the general stress level and yielding or propagation of the crack is likely for very modest values of σ.

Why should tensile stress be reduced?

Tensile stress level should be reduced as far as possible because the collar bears tensile stress, so that stress cracking can be prevented. If an API standard collar cannot meet the requirement, heavy wall tubing and casing and a heavy wall collar should be adopted. View chapter Purchase book. Read full chapter.

What causes stress in fractures?

Stress concentration occurs owing to the presence of cracks and sharp corners, causing rock failures; even the intact rock has a very high strength. Inglis and Griffith theories are introduced to study the stress and displacement relationships when fractures exist in the rock. Stress distributions around the fracture tips in three fracture modes are introduced. The stresses and fracture intensity factors in an inclined fracture under anisotropic far-field stresses are also discussed, which may be applicable for inclined wellbore and hydraulic fracturing problems. Sneddon's solutions of fracture widths in both 2-D and 3-D conditions are discussed, which can be applied to hydraulic fracturing modeling and wellbore strengthening design. Fracture propagation in rock is characterized by the generation of microcracks around the crack tip, i.e., an inelastic zone or the fracture process zone is formed. This zone is examined using fracture mechanics theory. The mechanical properties and stress-deformation behaviors in fractured rock mass are also discussed.

What is thread and connection?

Threads and connections are the weak links of tubing and casing. Designed pipe body stress should be lower than the environment fracture stress level. However, the stress level and stress concentration of thread and connection may be much higher than that of the pipe body.

How does electrical stress affect electrical field?

Electrical field stress concentrations can be occurred when the electricity enters from one cable to another cable and this sudden change in material create electrical field stress concentration. This stress can be assumed a common problem in many high- and medium-voltage applications such as cables accessories, generator, or motor end windings or bushing. This electrical stress concentration can create breakdown, flash over, and corona phenomena between fittings. In order to solve the problem, it is necessary to control the electrical field throughout materials and the conductivity and nonlinearity on changing conductivity in the materials to be properly controlled. Using functional graded materials (FGM) to control grading the electrical field is one of the solutions. Using FGM avoids local surface stress at interfaces, in such away that, which will not exceed the breakdown strength in any location. FGM application in insulators is described in the following chapters. Other solution method is that the electrical field to be distributed at fitting interface [8].

What leads to the breaking of atomic strong bonds that characterize the diamond compact structure?

Stress concentration leads to the breaking of atomic strong bonds that characterize the diamond compact structure.