Papers by Keyword: Inner Stress

Abstract: The residual stress in epoxy adhesive layer deposited on metal and other substrate at room temperature is studied. With embedded strain gauges in arranged depth of epoxy layer, the strain changes in the adhesive layer induced by the curing procedure and the changes of ambient temperature were measured to evaluate the changes of residual stress in place during a period after the curing procedure finished. The actual strain in epoxy adhesive layer from curing is used to estimate the residual stresses in it. While taking the strain obtained from the surface of the adhesive layer as free strain, the residual stress can be calculated and presented a strongly cyclic variation with a period of 24 h. The inner stress is also analyzed using the finite element method.

Abstract: The origin of the inner stress in the ceramics green bodies prepared by colloidal forming was studied. The results show that the inner stress originates from the nonuniform shrinkage during the solidification of the precursor suspension and the drying of the green bodies, and the gradients of temperature, initiator concentration and moisture are the important original factors causing the inner stress. The inner stress could result in cracks in the green bodies during debinding.