Test, testing flatness, flexure

Elastomer samples are cast in molds, the size and shape of which depend on its purpose. Samples for physical properties can be produced using a custom-made book mold designed to create a thin sheet (0.1 in.) containing premolded test parts, such as those for die-C tear, flexural modulus, and so on. Alternatively, a flat plaque mold may be used to create a 6 x 6 x 0.1-in. sheet from which may be cut samples for testing. Thicker samples for hardness measurements may... 

ASTM C 393-62 (1988) Standard Method for Flexure Test of Flat Sandwich Constructions, 3 pp (Comm F-7)... 

The modulus of elasticity in flexure is defined in an analogous way to the tensile and compressive tests, with the strains of 0.05% and 0.25"/o again taken as the limiting values between which it is determined. This places very severe constraints on the accuracy of the test equipment and the test piece itself. For the standard test piece. 0.05% strain corresponds to a deflection of the outer surface of only 0.08 mm from its starting point. This does not make much allowance for any backlash in the test jig. lack of flatness in the test piece, or lack of alignment in any of the three loading bars. 

Flexural fatigue testing of plastics using flat specimen... 

One of the advantages of the three methods in C 1421 is that they all use a simple bend bar. Each 3 mm x 4 mm x 45 mm to 47 mm bar test specimen was prepared in accordance with the generic ( standard ) preparation procedure specified in the flexural strength standards MIL STD 1942 MR," ASTM C 1161," and ISO 14704. ° One 4 mm wide face was finished with a 900 grit wheel (finer than is normally required) to produce a flat and smooth surface for the Knoop indentation in the SCF test method. The four long edges of the test specimens were chamfered in accordance with requirements for the surface crack in flexure (SCF) and precracked beam (SEPB) test methods. 

CMCs generally exhibit graceful failure from a cumulative damage process, unlike monolithic advanced ceramics that fracture catastrophically from a single dominant flaw. The flexure testing of CMC (both flats and tubes) has a range of different material and experimental factors that interact and must be controlled and managed (Table 1)... 

The filament wound flat specimens with a pre-crack were submitted to ENF-end notched flexural tests according to the determinations defined by protocol proposed by the ESIS task group [6]. The specimen geometry is schematically represented in figure la). The... 

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