Tensile properties strain, effects

The effect of temperature on PSF tensile stress—strain behavior is depicted in Figure 4. The resin continues to exhibit useful mechanical properties at temperatures up to 160°C under prolonged or repeated thermal exposure. PES and PPSF extend this temperature limit to about 180°C. The dependence of flexural moduli on temperature for polysulfones is shown in Figure 5 with comparison to other engineering thermoplastics. 

Elements that can dissolve in copper, such as zinc, tin, and nickel for example, increase annealed strength by varying amounts depending on the element and the quantity in solution. The effect of selected solution hardening elements on tensile properties of annealed copper aUoys is iUustrated by the data in Table 4, where the yield strength is the stress at 0.2% offset strain in a tensile test. 

Test rate and property The test rate or cross-head rate is the speed at which the movable cross-member of a testing machine moves in relation to the fixed cross-member. The speed of such tests is typically reported in cm/min. (in./min.). An increase in strain rate typically results in an increase yield point and ultimate strength. Figure 2-14 provides examples of the different test rates and temperatures on basic tensile stress-strain behaviors of plastics where (a) is at different testing rates per ASTM D 638 for a polycarbonate, (b) is the effects of tensile test-... 

It should be recognized that tensile properties would most likely vary with a change of speed of the pulling jaws and with variation in the atmospheric conditions. Figure 2-14 shows the variation in a stress-strain curve when the speed of testing is altered also shown are the effects of temperature changes on the stress-strain curves. When the speed of pulling force is increased, the material reacts like brittle material when the temperature is increased, the material reacts like ductile material. 

Where exposure to the liquid in service is intermittent it may be of interest to know the effect on properties after drying. ISO 175 [16] includes procedures for measuring tensile stress, strain and hardness after a drying period in an oven. Depending on the application, measurements before or after drying may be required and possibly both will be of relevance. 

An important feature of filled elastomers is the stress softening whereby an elastomer exhibits lower tensile properties at extensions less than those previously applied. As a result of this effect, a hysteresis loop on the stress-strain curve is observed. This effect is irreversible it is not connected with relaxation processes but the internal structure changes during stress softening. The reinforcement results from the polymer-filler interaction which include both physical and chemical bonds. Thus, deforma-tional properties and strength of filled rubbers are closely connected with the polymer-particle interactions and the ability of these bonds to become reformed under stress. 

To determine the effect of coating thickness on tensile properties, coating thicknesses of 0.25, 0.5, 0.75, 0.85, 1.0, 1.25 and 1.5 im of Parylene-C were applied to modern silk fabric. In Table 2, the breaking-load and strain-to-break are shown as a function of coating thickness, and a linear dependence is evident. A similar effect was observed when paper was coated with Parylene-C (5). 

Effect of Parvlene-C Coating on Historic Silk Fabric. The results of tensile testing of coated and uncoated historic silk fabric are given in Table 5. For modern, strong silk (original, uncoated breaking-load >250 N, strain-to-break >15%), a 0.75 )Un thick layer of Parylene-C increased the tensile properties, with the exception of the initial modulus, as was shown in Table 1. 

Figure 12 shows the influence of the nominal draw ratio on the tensile properties for the poly(ether ester) C. The initial tensile modulus was nearly independent of the draw ratio. A higher strains the modulus increased proportionally to the draw ratio. As can be seen from Fig. 13, the effect of the extrusion velodty on the tensile properties was rather small. 

Initial studies on PU1478 materials showed effects on physical properties of plaque thickness and System Index used during RIM processing. Typical tensile stress-strain data are given in the first 4 columns of Table III. Increases, particularly in modulus, elongation... 

Tensile properties of composite propellants depend on the tensile properties of the matrix, concentration of the components, particle size, particle-size distribution, particle shape, quality of the interface between fillers and polymeric binder, and, obviously, experimental conditions (strain rate, temperature, and environmental pressure). Many authors (2, 3) have explained the effect of fillers on the mechanical properties of composites, the importance of the filler-matrix interface on physical properties, and the mechanism of reinforcement of the material. Other efforts have examined the effect of experimental conditions on the failure properties of filled elastomers. Landel and... 

JH Holbrook and AJ West, The effect of temperature and strain rate on the tensile properties of hydrogen charged 304L, 21-6-9, and JBK 75 , in Hydrogen Effects in Metals, IM Bernstein and AW Thompson, Eds., The Metallurgical Society of AIME, New York, 1981, pp. 655-63. 

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