Tensile testing, 2.19

The plastic behaviour of a material is usually measured by conducting a tensile test. Tensile testing equipment is standard in all engineering laboratories. Such equipment produces a load/displacement (F/u) curve for the material, which is then converted to a nominal stress/nominal strain, or cT l , curve (Fig. 8.10), where... 

Tensile Tests. Tensile properties shall be determined by tests on longitudinal specimens conforming to the requirements of Paragraph 4.4 (see API Specification 5A) and ASTM A370 Mechanical Testing of Steel Products, Supplement II, Steel Tabular Products. 

The method of obtaining creep data and their presentation have been described however, their application is limited to the exact same material, temperature use, stress level, atmospheric conditions, and type of test (tensile, compression, flexure) with a tolerance of 10%. Only rarely do product requirement conditions coincide with those of the test or, for that matter, are creep data available for all grades of material that may be selected by a designer. In those cases a creep test of relatively short duration such as 1000 h can be instigated, and the information can be extrapolated to the long-term needs. It should be noted that reinforced thermoplastics and thermosets display much higher resistance to creep (Chapter 2). 

Instron for testing tensile strength, stress, strain, and creep characteristics... 

Tensile Testing. Tensile tests were run on an Instron 1000 using a 5.08 cm (2 Inch) guage length and a speed of 12.7 cm (5 lnches)/mln. The procedures In Burlington Test Procedure FP-015 (ASTM-D-579) were followed. At least 5 specimens of each sample were tested. Fabric tests results are quoted for the warp direction only. The percent retention of tensile strength was calculated from the equation % retention where F and F(j are the... 

Sulfui>-Aggregate Interaction. Substantial increases in stiffness of SA binder-based mixes, as measured by the Marshall test, tensile strength, and resilient modulus of elasticity, have been observed with increasing sulfur-asphalt ratio of the binder used (11, 15, 16). Such increases can, of course, be attributed in part to the increase in viscosity of the SA... 

Mechanical Testing. Tensile strength tests were performed with an Instron tensile tester as per the American Society for Testing and Materials (ASTM) D-1682, and tear testing was done with an Elmendorf apparatus as per ASTM D-1424 at 21 °C and 65% rh, after conditioning the specimens for at least 24 h. Results reported are the average of three tests. 

The plastic strains are measured by means of point marking method. The markings with 1 mm interval in a direction of tensile axis were made by a micro-vickers hardness tester before tensile tests. Tensile tests were conducted at room temperature at a cross-head rate of 0.5 mm/min with an Instron-type testing machine. After the tensile deformation, the relative displacements between markings were measured under a precision machinery microscope, and the corresponding local strains in the direction of tensile axis were calculated. Then deformed specimens were cut into pieces of 1 mm width by a low speed cutter perpendicular to the tensile axis. The saturation magnetization of each piece was measured by magnetic balance at room temperature. 

Relevant physical properties, e.g., leak test, tensile strength, moisture vapour transmission, closure removal torque... 

For the determination of wet T s, the fibers were allowed to soak In distilled water for 24 hi before testing. Tensile testing was carried out on an Instron tester with the fibers totally Immersed In water at the specified temperature. Testing was carried out at 0, 10, 23, 30, 40, 50, 60, 70, 80, 90,... 

Tensile Tests. Tensile tests were done on an Instron tensile tester un er ambient coi dition at strain rates, , ranging from 1.0 X 10 to 5.5 x 10 sec. Experiments were done in triplicate at each strain rate. Stress, a, and strain, , at yield (not shown) were determined using tSe 0.2% offset method (5). Stress,, and strain, , at break and the work to break, W, (the area under the stress-strain curve) were also calculated. The latter was evaluated via a computer program using a Simpson s Rule method. 

Precision of flexnral modulus measurements is usually fair. ASTM D 638-03 lists examples for several different plastics, including polypropylene, tested by eight laboratories nsing the Type I specimen, of nominal 0.125-in. thickness. Each test result was based on five individual determinations. Each laboratory obtained two test results for each material. For polyethylene, tensile modnlns of elasticity was 210,000+8900 psi for within-laboratory tests and 210,000+71,000 psi for between-laboratory tests. Tensile strength at yield for polypropylene was 3630+22 psi for within-laboratory tests and 3630+161 psi for between-laboratory tests. Elongation at yield was 8.79+0.45 and 8.8+5.9% for within- and between-laboratory tests, respectively. 

The various benchmark values set by EN 13795 for surgical gowns, surgical drapes, and clean air suits are found in Tables 5.8—5.10, respectively. The industrial test methods, in addition to common strength tests (tensile, tear, and bursting), comfort, and absorbency, normally carried out on hospital protective textiles are presented in (Table 5.11). 

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. 

Table 3. Test tensile value of rope exchange vehicle. 

The stress-strain test (tensile test) is the most common mechanical test used for polymers. This test is conducted by fixing the polymer sample at one end to a loading frame, and a force is applied at the other end to achieve a controlled displacement d (see Figure 20.1a). A stress-strain curve (Figure 20.1b) is obtained and analyzed to provide the mechanical properties. The stress (defined using the following equations ... 

Pre] Specimens dimensions and volumes determination Vickers microhardness and hardness tests tensile tests Sintered density interconnected porosity volume shrinkage microhardness and hardness tensile strength... 

Lim] Mechanical testing Tensile strength, tensile elongation ... 

Quasi-static tensile test - tensile properties of thermoplastics - data... 

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