Tempered glass tensile

Tempered glasses are useful because failure normally occurs under an applied tensile stress, and failure in ceramics and glasses is almost always initiated at the surface. When a permanent compressive stress, called a residual compressive stress, is placed on a surface, either through thermal or chemical means, the applied stress must first overcome this residual compression before the surface is brought into tension under which failure cau occur (see Figure 5.53). Notice that the residual stress is compressive in nature at the surface of the plate and is tensile in the center (shaded areas). When... 

The failure of ceramic materials almost always results from a crack that is initiated at the surface by an applied tensile stress. To cause fracture of a tempered glass piece, the magnitude of an externally applied tensile stress must be great enough to first overcome the residual compressive surface stress and, in addition, to stress the surface in tension sufficient to initiate a crack, which may then propagate. For an untempered glass, a crack is introduced at a lower external stress level, and, consequently, the fracture strength is smaller. 

Glass fibres Diameter Length Tensile Young s strength modulus Density Critical Water Soften. strain uptake temper. ... 

Incorporation of CNT into polymer matrix, due to the exceptional properties and laige aspect ratio, has been proven to be a promising approach leading to stmctural materials and composites with excellent physical and mechanical properties such as tensile strength, tensile modulus, strain to failure, torsional modulus, compressive strength, glass transition temper-... 

Hence, for compressive residual stresses, fracture happens under greater applied stresses than for the residual stress-free state. In feet, tempering is used commonly to strengthen the glass surface. As discussed in Chapter 6, compressive stresses build at the surface and are equilibrated by tensile stresses in the core of... 

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