Tensile tests factors affecting

As we saw in the preceding discussion, several mechanical parameters can be derived from stress-strain tests. Two of these parameters are of particular significance from a design viewpoint. These are strength and stiffness. For some applications, the ultimate tensile strength is the useful parameter, but most polymer products are loaded well below their breaking points. Indeed, some polymers deform excessively before rupture and this makes them unsuitable for use. Therefore, for most polymer applications, stiffness (resistance to deformation under applied load) is the parameter of prime importance. Modulus is a measure of stiffness. We will now consider how various structural and environmental factors affect modulus in particular and other mechanical properties in general. 

Strain curve is provided. They can be programmed to be extremely useful in quality control. See testing, tensile testing-machine test rate The speed at which its cross-head moves. An increase in strain rate typically results in an increasing yield point and strength. Test methods specify speed of testing for the different materials (soft to rigid) to be tested since test results can be affected by the time-dependent factor. 

The second important factor affecting low temperature embrittlement of the 7000 series aluminum alloys is that of primary working. The degree of primary working of the metal is important as maybe seen by comparing the properties of the 7079 T6 sheet and 7079-T6 billet material. Their analyses were nearly identical however, the billet material experienced much more severe embrittlement at lower temperatures than the sheet material. This may be explained by the cored structure present in the 7079-T6 billet (Fig. 10), which was not broken up by primary working. No effects of heat treatment were detected since all materials tested were of the same temper and improper heat treatment was not apparent from the tensile data or microstructures. 

Qther factors may affect the results so this project will take into account changes in the polymer due to process conditions and geometry. By melt flow index testing the material and ground parts, and tensile testing the molded tensile bars this can be accomplished. 

However, as RH further increases, tablet strength decreases for most tested tablets, and it was suggested that condensed water on the solid surface at high RH weakens intermolecular attraction forces between particles in the tablets and the further softened particles and solid bonds cause the tensile strength to decrease. " In addition, at high RH, water may form multilayers on the solid surface, which can act as a lubricant and reduce the frictional forces between particles, thus decreasing tensile strength as well. Ultimately, the effects of adsorbed moisture on particle surfaces are very complex, affected by many factors, especially the properties of the tablet excipients. 

The fabric substrate used for the filter media will need to provide certain characteristics, dependent on the application. The typical properties required include abrasion resistance, stretch resistance, dimensional stability, and resistance to flex fatigue. All these performance criteria can be assessed by using suitable test methods. The fabric will also be tested for correct warp and weft sett, air permeability, thickness, density, and fabric tensile properties. All the factors will affect the performance of the filter as they are directly related. If woven fabrics are considered, the porosity will be directly related to the sett and therefore air permeability. The combinations of the fibre types, fabric constructions, and coating substrate will provide the filter manufacturer with a range of properties for use in a range of appUcations. 

The stmctural and material properties similar to native ACL are one of the essential factors for the graft substitute in reconstmction surgery. The ultimate tensile load of native ACL reported in literature was varied 1725-2160 N. It might be affected by difference in the size of tested specimens, the age of donor, and the setting of biomechanical testing [13, 14]. 

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