Composite materials failure criteria

The strength of laminates is usually predicted from a combination of laminated plate theory and a failure criterion for the individual larnina. A general treatment of composite failure criteria is beyond the scope of the present discussion. Broadly, however, composite failure criteria are of two types noninteractive, such as maximum stress or maximum strain, in which the lamina is taken to fail when a critical value of stress or strain is reached parallel or transverse to the fibers in tension, compression, or shear or interactive, such as the Tsai-Hill or Tsai-Wu (1,7) type, in which failure is taken to be when some combination of stresses occurs. Generally, the ply materials do not have the same strengths in tension and compression, so that five-ply strengths must be deterrnined ... 

As with the maximum stress failure criterion, the maximum strain failure criterion can be plotted against available experimental results for uniaxial loading of an off-axis composite material. The discrepancies between experimental results and the prediction in Figure 2-38 are similar to, but even more pronounced than, those for the maximum stress failure criterion in Figure 2-37. Thus, the appropriate failure criterion for this E-glass-epoxy composite material still has not been found. 

The Tsai-Hill failure criterion appears to be much more applicable to failure prediction for this E-glass-epoxy composite material than either the maximum stress criterion or the maximum strain failure criterion. Other less obvious advantages of the Tsai-Hill failure criterion are ... 

For E-glass-epoxy, the Tsai-Hill failure criterion seems the most accurate of the criteria discussed. However, the applicability of a particular failure criterion depends on whether the material being studied is ductile or brittle. Other composite materials might be better treated with the maximum stress or the maximum strain criteria or even some other criterion. 

R. C. Tennyson, D. MacDonald, arrd A. P. Nanyaro, Evaluation of the Tensor Polynomial Failure Criterion for Composite Materials, Journal of Composite Materials, January 1978, pp. 63-75. 

An essential step in developing an interactive reliability model requires formulating a deterministic failure criterion that reflects the limit state behavior of the material. Miki et al.,21 and de Roo and Paluch22 have adopted this approach in computing the reliability of unidirectional composites. In both articles, the Tsai-Wu failure criterion is adopted, where different failure behavior is allowed in tension and compression, both in the fiber direction and... 

Recognizing that most failure criteria are limited in their accuracy [8,9], researchers worldwide have undertaken collaborative efforts to evaluate different failure criteria to determine their accuracy and applicability in order to find the best one [10]. These efforts, in particular the worldwide failure exercise in [10], have underlined the fact that despite the large number (over 20) of failure criteria, there is no single one that seems to capture failure of composites accurately for a wide range of loading situations and materials. However, they have pointed out that certain criteria are more accurate and/or have a wider range of applicability than others. Most notable among these are the Puck criterion and the LaRC 03 failure criterion. 

The scale dependence on strength can be explained by utilizing the point stress failure criterion, that is used with polymer matrix composites [168,169], as well as by considering the statistics offiber strength distribution [148]. These models suggest a characteristic length scale of 0.5 mm over which the stress must exceed the strength of the material in order for failure to initiate. 

The above understanding forms the basis for the development of thermophysical and thermomechanical property sub-models for composite materials at elevated and high temperatures, and also for the description of the post-fire status of the material. By incorporating these thermophysical property sub-models into heat transfer theory, thermal responses can be calculated using finite difference method. By integrating the thermomechanical property sub-models within structural theory, the mechanical responses can be described using finite element method and the time-to-failure can also be predicted if a failure criterion is defined. 

Without enquiring into the chemical mechanisms of adhesion, workers in the engineering field, and specifically that of applied mechanics, continue to examine the behaviour of composite materials made into artefacts of simple geometry such as plates and tubes. Thus Eckold et apply a macroscale criterion of failure, in fact a simple limiting maximum stress, and a rule of mixtures of the equation (4) type, to determine both the failure mode and failure load of filament-wound glass reinforced polyester pipes. 

Qiao P, Wang J et al (2003b) Tapered beam on elastic foundation model for compliance rate of change of TDCB specimen. Eng Fract Mech 70 339-353 Reeder JR (1993) A bilinear failure criterion for mixedmode delamination. In Camponeschi ET (ed) Composite materials testing and design, vol 11. ASTM STP, Philadelphia, pp 303-322... 

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