Toughening by partial or full bridging of cracks in ceramics and fiber reinforced composites

摘要: Abstract A complete solution is given for a fully or partially bridged straight crack in transversely isotropic elastic materials which may correspond to unidirectionally fiber-reinforced ceramics other brittle composites. The stiffness of the bridging have an arbitrary variation along crack, representing failed fibers ligaments. any orientation with respect axis material symmetry. explicit terms Chebychev polynomials when bridging-forces are linearly dependent on crack-opening-displacement. In addition, uniformly valid asymptotic solutions developed cracks. For case short relative length scale depends properties, method yields forces non-linearly crack-opening-displacement (a square-root dependence, corresponding continuous fibers, used illustration). long cracks, proposed effective, but results not presented this work. mechanism kinking studied oblique bridged, unbridged macroscopically solid. assumed grow matrix (containing unbroken strong fibers) under local driving calculated basis overall anisotropic response. various fracture criteria studied. It illustrated that, far-field tensile normal criterion maximum opening mode stress intensity factor homogenized solid (i.e., strength singularity associated hoop maximum) produces suggest growth more less parallel whereas based Mode I and/or symmetry (again, matrix) predict extension reinforcing fibers.