Double cantilever beam measurement and finite element analysis of cryogenic Mode I interlaminar fracture toughness of glass-cloth/epoxy laminates

An experimental and analytical investigation in cryogenic Mode I interlamin ar fracture behavior and toughness of SL-E woven glass-epoxy laminates was conducted Double cantilever beam (DCB) rests were performed at room tempera ture (R.T.), liquid nitrogen temperature (77 K), and liquid helium temperat ure (4 K) to evaluate the effect of temperature and geometrical Variations on the interlaminar fracture roughness. The fracture surfaces were examined by scanning electron microscopy to verify the fracture mechanisms. A finit e element model was used to perform the delamination crack analysis. Critic al load levels and the geometric and material properties of the test specim ens were input data for the analysis which evaluated the Mode I energy rele ase rate at the onset of delamination crack propagation. The results of the finite element analysis are utilized to supplement the experimental data.