Transverse bending test

The white, opaque bodies fabricated in this manner have a density of 95-98% of theoretical and contain interconnected channels of uniformly sized pores of 50 nm average diameter, distributed throughout the dense amorphous silica matrix. These bodies are over twice as strong as optical grade fused sihca, as measured by transverse bend tests on specimens of equal size cut in the same way by diamond sawing. 

At a content of 2 mg/g however, cracks already appear at a deformation of 25 %. Tantalum on the contrary already becomes brittle at oxygen contents of 200/tig/g. The transition temperature brittle/ductile, which depends on the oxygen content, is of a special practical importance for pure metals. Determined by the transverse bending test the transition temperature of niobium is approx. - 200°C when the oxygen content is 200 jug/g for an oxygen content of 1000 g/g it is - 30°C and for 2000 /ig/g + 20°C. 

The stress-strain behaviors and fracture strengths of ceramic materials are determined using transverse bending tests. 

Flexural strengths as measured from three-point transverse bending tests may be determined for rectangular and circular cross-sections using, respectively. Equations 12.7a and 12.7b. 

In this paper the influence of the level of thermal residual stresses on the development of transverse cracking in cross-ply carbon-polyetherimide laminated beams subjected to bending has been considered. Different levels of ply-to-ply residual stresses were obtained by producing cross-ply ([90/0]s) laminates having different lay-ups in the 0° layer. Two methods were used to analyse the bend tests. The first considered the stress at the formation of the first transverse crack, the second the energy released at the formation of this crack. 

Tensile testing of ceramics is time-consuming and expensive because of the difficulty in machining test specimens. Instead, the simpler transverse bending or flexure test is used, where the specimen is loaded to failure in either... 

The transverse bending tensile strength is a more direct measure of the interfacial strength than the short-beam test. The transverse tensile fracture surface is directly accessible, but the test is more time consuming than the short-beam test because the edges must be sawn very carefully. 

The measured increase due to the aramid adhesion treatment was different for each test 60 % in bundle pull-out, = 28 % in the 3-point, s 40 % in the 4-point short-beam and, = 60-80 % in transverse bending strength. Further improvement of the off-axis strength of aramid-epoxy composites is limited by the shear and transverse strength of the aramid fibres. In spite of the considerable adhesion improvement aramid-epoxy composites still have a lower shear and transverse strength than glass and carbon fibre composites. However, the corresponding strains are approximately equal because of the lower aramid-epoxy shear and transverse moduli. 

Cross-bend Test. (1) Term sometimes used for transverse strength test (q.v.). 

Fig. 12. Curvature responses of decapitated avena coleoptiles as a function of auxin concentration. (A) curvature obtained in 90min, auxin applied asymmetrically (standard auxin test). (B) curvature produced in 60 min by symmetrical application of auxin upon succeeding transverse electrical stimulation. Bending occurs towards the positive pole, as sketched187 ...

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