Uniform compressive stress

If it is assumed that uniform tensile stress, like uniform compressive stress (7), has no significant effect on yield, then the yield pressure of a cylinder subjected solely to an internal pressure may be calculated from... 

The data in Figure 11 is organized into stress distribution diagram shown in Figure 12. The section stress is decomposed into three parts uniform compressive stress caused by horizontal force Stress caused by a plane linkage effect moment stress caused by the additional bending moment AM<. The formation of and the resulting stress effect, which is not the normal steady state, is due to the entire line beam arch effect and complex stress state of break point position. Comprehensive stress factor (p should be added to the mechanical analysis process. 

Fig. AIA.2 Theoretical and experimental transverse stresses for a ja = 0.50 expressed as 1 ratio of the uniform compressive stress...

Second - Uniform compressive stress applied to the anchorage zone increases the load carrying capacity of the anchorage unit, the maximum tensile strain at cracking being increased. 

In pi actice, loads are not necessarily uniformly distributed nor uniaxial, and cross-sectional areas are often variable. Thus it becomes necessary to define the stress at a point as the limiting value of the load per unit area as the area approaches zero. Furthermore, there may be tensile or compressive stresses (O,, O, O ) in each of three orthogonal directions and as many as six shear stresses (t, , T ). The... 

Significantly, a flexural specimen is not in a state of uniform stress. When a simply supported specimen is loaded, the side of the material opposite the loading undergoes the greatest tensile loading. The side of the material being loaded experiences compressive stress (Fig. 2-16). These stresses decrease linearly toward the center of the sample. Theoretically the center is a plane, called the neutral axis, experiences no stress. 

In providing an overall picture of the Griffith theory applied to the comminution process, it must be pointed out that the theory requires that a tensile stress should exist across a crack to open it further. While a uniform compressive force can close a crack, a nonuniform one can lead to the occurrence of localized tensile stresses. In a comminution process the particles are subjected to nonuniform loading, and therefore it can be surmised that they normally break in tension and not in compression. However, the tensile component of loading in comminution does not form the major loading component and this contributes towards a lowering of the overall energy efficiency of comminution. 

The thermal expansion coefficient of silicon is approximately seven times larger than that of Si02, as given in Table 2. When Si02 is deposited, typically at temperatures of several hundred degrees C, an in-plane compressive stress develops in the oxide layer as the Si wafer is cooled by AT to room temperature. For a uniform 2-dimensional thin film deposited on a substrate, the in-plane stress obtained from Equation 2 is ... 

The creep stress was assumed to be shared between the polymer structure yield stress and the cell gas pressure. A finite difference model was used to model the gas loss rate, and thereby predict the creep curves. In this model the gas diffusion direction was assumed to be perpendicular to the line of action of the compressive stress, as the strain is uniform through the thickness, but the gas pressure varies from the side to the centre of the foam block. In a later variant of the model, the diffusion direction was taken to be parallel to the compressive stress axis. Figure 10 compares experimental creep curves with those predicted for an EVA foam of density 270 kg m used in nmning shoes (90), using the parameters ... 

Closed-cell foams made from metallocene-based polyolefins (MPO) have potential for use in various applications because of their uniform composition and low toxicity. Compressive stress relaxation is used to investigate the behaviour of these foams. In particular, its behaviour is compared with open-cell PU foams, a material MPO foams could possibly replace. The effect of gamma radiation on MPO foam behaviour is also... 

For an externally applied pressure, a compression-compression stress field is obtained with a thick-walled sphere. If the sphere wall is thin, a biaxial field is produced. If the pressure is applied internally, a triaxial tension-tension-compression state is generated. A nearly uniform stress field is produced over the entire specimen. The supporting tube is surrounded with a low modulus material to avoid stress concentration and... 

Contours of maximum principal stress in the first slice (near the gas inlets) and the sixth slice (near the gas outlet) are shown in Figures 5.11 and 5.12 respectively. It can be seen that the stack is partially under compression and partially under tension due to the mismatch in the thermal expansion coefficient of the materials and non-uniform temperature. In each cross-section, the stresses are higher near the top of the stack than near the bottom. Also, the stresses are higher near the gas outlet than near the gas inlets. Maximum tensile and compressive stresses in all the slices are found to be 60 MPa and 57.2 MPa respectively which are in the electrolyte layer of the last slice. The maximum stresses in all the layers are found to be well within the failure limits of their respective materials and hence thermal stress failure is not predicted for this stack. 

Therefore, neither the appreciable plastic deformation (both in the case of uniform compression and of local fracture) of the solid reaction systems studied nor their static state of high stress is a factor conditioning the critical phenomena and autowave processes observed during the chemical conversion in the systems. In other words, this series of experiments has provided another telling argument for the decisive role of brittle fracture in the mechanism of the phenomena considered. 

The jump from uniaxial elongation to uniform compression is a simple one in terms of defining all the stresses and strains. The final modulus we wish to define, the shear modulus., r, is a little different and you have to pay... 

When a rod of uniform cross-section supports a weight, the rod will be subjected to tensile stress if the weight hangs from the rod and to compressive stress if the weight rests on the rod, as shown in Fig. 5.1. 

The canning process applies a biaxial compressive stress on the lateral surface of catalyst support via compression of the mat. In the case of a circular substrate, the canning pressure is uniform and well below its biaxial compressive strength p2o [46]. The latter is related to isostatic strength via... 

Figure 48-9 Shear keys protruding from the liner face permit relatively light structural sections (buckstays) to transmit uniform band reactions directly into the liner brickwork as compressive stresses.

The number of bolts and the bolt size must be chosen such that the bolt load is less than the maximum allowable stress in the bolts. The bolt spacing must be selected to give a uniform compression of the gasket. It will not normally be less than 2.5 times... 

The radial and tangential residual thermal stress in TiC sphere is a uniform compressive... 

At the other extreme, after an infinite time, the load is supported wholly by the elastic host, the fluid stops flowing and the fluid pressure is not only hydrostatic at each local point but spatially uniform as well. This means that at all fluid-solid interfaces, the stress in the solid has a component normal to the interface of some magnitude P (see Figure 10.1) it is only in the solid s interior, away from any flat-lying fluid interface, that vertical compressive stresses with magnitude greater than P can exist and support the load. 

If two polymorphs are strongly bonded at a planar interface and subjected to a constriction stress field about the interface s normal as the constriction axis, for the strain to be uniform the compressive stress profile must be exponential. Within a few nanometers of the interface, stress gradients and diffusion of material become noticeable. Equation (12.6) applies and Figure 13.3 illustrates the results. 

As regards stress state, let this be uniform throughout the host material except insofar as the inclusion causes variation let the remote stress state have principal compressive stresses and with larger. To start, we make the same assumptions as in Chapter 13, namely that the two materials are uniform and of the same chemical composition, differing only in viscosity and let the material of the inclusion be stiffen... 

Compressive properties include compressive strength, modulus of elasticity, yield stress, and deformation beyond yield point. The ASTM procedure covers determinations of all of them. In all cases, tested specimens are loaded in compression at relatively low uniform rates of straining or loading. Compressive yield point is the first point on the stress-strain curve at which an increase in strain occurs without an increase in stress. In other words, it is the load under which the specimen starts to move continuously without an increase in the load. Also, many plastic materials will continue to deform in compression until a flat disk is produced, without breaking of the specimen. In those cases the compressive stress (nominal) increases steadily in the process, without failure of the material. Compressive strength typically has no meaning in such cases. 

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