Analysis Of Transverse Cracking Research Articles

Quantitative Analysis of Transverse Cracking of Rail Using Eddy Current Non-Destructive Testing

In this study, we analyzed transverse cracks in rails using eddy current testing. Quantitative analysis was performed on transverse crack defect signals ascertained by actual flaw detection and finite element simulation of the rail that had developed a central transverse crack. The conductivity and width of the finite element model were equivalent to those of the actual rail. By analyzing the distribution of eddy current on the rail surface, the relationship between the variation in the density of eddy current and size of transverse crack was obtained. Experimental and simulation results indicated that the application of eddy current testing in quantitative analysis of a rail flaw was feasible and would be a valuable reference in future research.

Analysis of transverse cracking and stiffness loss in cross-ply laminates with hygrothermal conditions

The change in longitudinal modulus as a result of transverse ply cracking in simple cross-ply laminate is examined theoretically with the taking into consideration the decrease of the mechanical properties of material by the variation of temperature and moisture. The results show that the hygrothermal environment has a significant effect on the relative reduction of longitudinal Young’s modulus at the higher crack density, in contrast with the complete reduction of longitudinal Young’s modulus in which the sensitivity of the hygrothermal effects become weaker but significant at the lower crack density.

Statistical damage analysis of transverse cracking in high temperature composite laminates

High temperature polymer composites are receiving special attention because of their potential applications to high speed transport airframe structures and aircraft engine components exposed to elevated temperatures. In this study, a statistical analysis was used to study the progressive transverse cracking in a typical high temperature composite. The mechanical properties of this unidirectional laminate were first characterized both at room and high temperatures. Damage mechanisms of transverse cracking in cross-ply laminates were studied by X-ray radiography at room temperature and in-test photography technique at high temperature. Since the tensile strength of unidirectional laminate along transverse direction was found to follow Weibull distribution, Monte Carlo simulation technique based on experimentally obtained parameters was applied to predict transverse cracking at different temperatures. Experiments and simulation showed that they agree well both at room temperature and 149 °C (stress free temperature) in terms of applied stress versus crack density. The probability density function (PDF) of transverse crack spacing considering statistical strength distribution was also developed, and good agreements with simulation and experimental results are reached. Finally, a generalized master curve that predicts the normalized applied stress versus normalized crack density for various lay-ups and various temperatures was established.

Modelling the transverse cracking in cross-ply laminates: application to fatigue

When cross-ply laminates are subjected to tensile loading, the transverse cracking is the early stage of damage which occurs. In the case of static loading, cracks are initiated on the edges of test specimens and cross instantaneously the whole width of the specimens. The analysis of the transverse cracking is then reduced to a two-dimensional problem. A generalized model of the transverse cracking, including progressive shear within the 0° layers is presented. In the case of fatigue tests, matrix cracks in 90° layers initiate at the free edges of test specimens and grow slowly across the specimen width as a function of cycle number. So, the analysis of transverse cracking has to be implemented using a three-dimensional model. The finite element analysis shows how it is possible to reduce this problem by dividing the test specimen into bands along its width, using then the previously derived generalized model in each band. Next, the paper presents a simulation of the progression of the damage based on a statistical distribution within the volume of the test specimen for the criterion of the damage progression.

Analysis of transverse cracking in cross-ply composite laminates

An analytical model based on the principle of minimum potential energy is developed and applied to determine the two-dimensional thermoelastic stress state in cross-ply composite laminates containing multiple equally spaced transverse cracks in the 90° plies and subjected to tensile loading in the longitudinal direction. The model provides full field solution for displacements and stresses including the residual thermal stresses which in turn are used to calculate the strain energy release rate associated with various failure modes. The strain energy release rate criterion has been employed to evaluate the critical applied stresses for two of the possible fracture modes; self-similar extension of a pre-existing flaw and the formation of a new parallel crack. The computed results indicate that formation of new cracks never takes place until pre-existing cracks extend through the entire thickness of the 90° plies. The predicted results of transverse crack density are in good agreement with the available experimental data.