| This research uses both experimental and analytical mechanics approaches to understand the roles that stiffness, strength and interfacial adhesion play in the deformation and fracture of an inclusion material sandwiched between layers of dissimilar material. These results have application beyond the experimental calendering problem considered here, which include composite materials, geologic structures, food processing, paper finishing, fabric finishing, and some electronics applications.;The objective is to establish the key factors in the fracture of the inclusion within a polymer/metal-alloy composite during calendering and enhance fundamental understanding of the process mechanics. We present the fracture patterns of NiTi and Ti inclusions sandwiched within several polymeric matrix of polycarbonate, polypropylene, or high density polyethylene, and we analyze the load transfer through the system.;To properly describe the load transfer, we studied the rheological properties of the polymers as well as the adhesion between the metal and the matrices. We developed a detailed analytical description of the load transfer and used it to predict the pressure and velocity distribution as well as the surface shear force and tensile stress distribution in the metal.;Analytical solutions were developed for both an incompressible Newtonian and power-law flows and the influence of several dimensionless parameters on the stress profiles was investigated. A system able to record in real-time the contact pressure on the interface between the sandwich sample composite and the rotating cylinders was used to validate the pressure profile obtained with the model. The model predicts closely the pressure profile on the sample in the nip gap between the rollers. The predicted maximum tensile stresses in the inclusion for the Newtonian and Power law models are within an order of magnitude as the ultimate strength of the metal.;It was found that there is a logarithmic relation between the stretch of the composite and the dimensionless nip gap when the samples were rolled to obtain fracture in the metal during the first rolling pass. The experimental work confirmed that the adhesion strength between the constituents does not explain the fracture behavior observed. |
