Material Properties of Selected Prosthetic Laminates

Abstract

In Brief To initiate a database on material properties of typical laminations used in prosthetic limb sockets, the authors subjected samples of common prosthetic laminations to tensile and bending tests. Eight varieties of lay-up materials (fibers) were each laminated separately with one of three common resins (matrix), resulting in 24 combinations of fiber/resin laminates. In addition to composition, the bending responses of various carbon fiber laminations were measured to evaluate the role of layer placement on bending strength. Results showed that formulations grouped into three categories based on mechanical strengths: the weakest were laminates with fibers of perlon or nyglass stockinette, spectralon, nylon, and cotton, ranging between 18 and 42 megapascals (MPa); the midrange was fiberglass, ranging between 67 and 109 MPa; the highest strengths were found in carbon fiber laminates, ranging between 236 and 249 MPa. Lamination Resin 80-20 (IPOS, Bauerfeind Prosthetics, USA, Kennesaw, GA) had higher ultimate tensile strength (UTS) than did Laminhartz 80-20 (Otto Bock, Healthcare, Minneapolis, MN) for perlon, nylon, cotton, nyglass, spectralon, fiberglass matte, and fiberglass cloth. Lamination Resin 80-20 had higher UTS than did Epoxyacryl (Foresee, Orthopedic Products, Oakdale, CA) for nyglass. Epoxyacryl had higher UTS than did Laminhartz 80-20 for nylon, cotton, spectra, and fiberglass cloth. No significance was achieved for carbon cloth. Bending tests on carbon fiber lay-ups showed that strength increased as the separation between layers increased linearly with R2 = 0.868. These data provide a preliminary database of material strengths of typical laminations and suggest the utility of minimum standards for prosthetic laminations. To initiate a database on material properties of typical laminations used in prosthetic limb sockets, the authors subjected samples of common prosthetic laminations to tensile and bending tests. Eight varieties of lay-up materials (fibers) were each laminated separately with one of three common resins (matrix), resulting in 24 combinations of fiber/resin laminates. In addition to composition, the bending responses of various carbon fiber laminations were measured to evaluate the role of layer placement on bending strength. Results showed that formulations grouped into three categories based on mechanical strengths. These data provide a preliminary database of material strengths of typical laminations and suggest the utility of minimum standards for prosthetic laminations.