In a convenient hardcover format this extensive source of crack stress analysis has been brought up-to-date with the addition of 150 new pages of analysis and information. The book is an excellent reference, as well as a text for in-house training courses, in various industrial and academic settings.
In a preceding study led by the authors [24,25,26], the efficiency of different CFRP repair configurations, in order to prolong the fatigue lifetime of both mild steel and wrought iron un-symmetrical cracked steel plates, was proven. Non-pre-stressed and pre-stressed normal modulus (NM) CFRP laminates as well as ultra-high modulus (UHM) CFRP laminates were studied, with both single and double-sided repairing configurations. In riveted structures, due to the presence of multi-plate components, the accessibility to both sides of the cracked element is often impossible. Therefore, the single-sided reinforcement was more particularly studied. As the efficiency of such reinforcement was experimentally proven, the next step was to develop reliable analysis tools to predict the behavior of the repaired elements.
The Stress Analysis Of Cracks Handbook Tada
The value of material constants C and m are the same for the fatigue analysis of the repaired specimens. That means that the effect of the CFRP patch only acts as a reduction of the stress intensity factor.
The steel plate, the CFRP laminate and the adhesive layer were modeled by using hexahedral mesh elements (8-node elements). The meshing was refined in the vicinity of the crack tip due to the existence of high stress concentration, while bigger elements were used near the plate edges, as shown in Figure 4. The element type and size were chosen through a sensitivity analysis in order to ensure that the finite element model (FEM) was able to make reliable predictions of the SIF. In this way, a mesh size of 0.5 mm in the width of the steel plate in the vicinity of the crack tip was considered. A through-thickness straight crack was set at the edge of the hole corresponding to the initial crack.
Figure 7 shows a good prediction of the crack propagation using the FEM (good correlation with the experimental results). From a crack length of 20 mm and above, an increase of the crack propagation rate was observed experimentally, corresponding to the end of the stable crack propagation field of the Paris law (as the inelastic region at the crack tip extends, the elastic stress analysis becomes inexact, and thus Equation (1) becomes no longer valid). 2ff7e9595c
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