Test method tensile

Table 3 compares properties of PTT, PET, and PBT (40). They were measured on injection-molded samples using ASTM test methods. Tensile strength, flexural modulus, and notched Izod impact of PTT fall in between those of PET and PBT. All three polymers have similar electrical properties except for PET which has lower volume resistivity. The lower moisture absorptions of PTT and PBT are due to the high crystallinities from fast crystallization. 

ASTM D2990, a. Test Methods for Tensile, Compressive andFlexural Creep and Creep Rmpture of Plastics, Vol. 8.02, ASTM, Philadelphia, Pa., 1993. 

Data for thermal movement of various bitumens and felts and for composite membranes have been given (1). These describe the development of a thermal shock factor based on strength factors and the linear thermal expansion coefficient. Tensile and flexural fatigue tests on roofing membranes were taken at 21 and 18°C, and performance criteria were recommended. A study of four types of fluid-appHed roofing membranes under cycHc conditions showed that they could not withstand movements of <1.0 mm over joiats. The limitations of present test methods for new roofing materials, such as prefabricated polymeric and elastomeric sheets and Hquid-appHed membranes, have also been described (1). For evaluation, both laboratory and field work are needed. 

Because of the simplicity of the first test method, most of the comparisons are made usiag this technique. The effects of the aging process are usually measured on tensile properties such as tensile strength, elongation, and stress (modulus) at 300% elongation (42). 

Test Method for Tensile Stress—Strain of Carbon and Graphite... 

Even if the process were at steady state, tensile strength, a key property would still reflect some variation. Steady state, or stable operation of any process, has associated with it a characteristic variation. Superimposed on this is the testing method, which is itself a process with its own characteristic variation. The observed variation is a composite of these two variations. 

ASTM C 749-92, "Standard Test Method for Tensile Stress-Strain of Carbon and Graphite". ASTM Standards Vol. 15.01, pp. 196 207, Pub. American Society for Testing of Materials, Philadelphia, USA (1994). 

These latter curves are particularly important when they are obtained experimentally because they are less time consuming and require less specimen preparation than creep curves. Isochronous graphs at several time intervals can also be used to build up creep curves and indicate areas where the main experimental creep programme could be most profitably concentrated. They are also popular as evaluations of deformational behaviour because the data presentation is similar to the conventional tensile test data referred to in Section 2.3. It is interesting to note that the isochronous test method only differs from that of a conventional incremental loading tensile test in that (a) the presence of creep is recognised, and (b) the memory which the material has for its stress history is accounted for by the recovery periods. 

It should also be noted that in this case the material was loaded in compre-sion whereas the tensile creep curves were used. The vast majority of creep data which is available is for tensile loading mainly because this is the simplest and most convenient test method. However, it should not be forgotten that the material will behave differently under other modes of deformation. In compression the material deforms less than in tension although the efrect is small for strains up to 0.5%. If no compression data is available then the use of tensile data is permissible because the lower modulus in the latter case will provide a conservative design. 

Standard Test Method for Tensile Properties of Plastics. D638-84. American Society for Testing and Materials Philadelphia, 1985, Vol 8.01, p 227. 

Compare flexural and tensile modulus testing methods. Why is it reasonable to say that both methods describe the rigidity of a material ... 

D0882-02 Test Method for Tensile Properties of Thin Plastic Sheeting, Annual Book of ASTM Standards, Vol. 08.02 Plastics , ASTM International, West Conshohoken, 2007. 

ISO 3597-2 2003 Textile-glass-reinforced plastics - Determination of mechanical properties on rods made of roving-reinforced resin - Part 2 Determination of flexural strength ISO 5893 2002 Rubber and plastics test equipment - Tensile, flexural and compression types (constant rate of traverse) - Specification ISO 6721-3 1995 Plastics - Determination of dynamic mechanical properties - Part 3 Flexural vibration - Resonance-curve method... 

ISO 9653 1998 Adhesives - Test method for shear impact strength of adhesive bonds ISO 9664 1993 Adhesives - Test methods for fatigue properties of structural adhesives in tensile shear... 

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