ELASTIC-CONSTANTS OF A MATERIAL WITH ORTHORHOMBIC SYMMETRY - AN ALTERNATIVE MEASUREMENT APPROACH

An alternative approach to measuring the complete anisotropic elastic constants c(ij)(s(ij)) of an orthorhombic-symmetry material is propose d. This approach requires measurements along only principal directions : (100). In this approach, a pulse-echo (megahertz-frequency) method w as used to measure c11, c22, c33, c44, c55, and c66. A resonance (kilo hertz-frequency) method was used to measure three elastic compliances: s11, s22, and s33. Combining the c(ii) with the s(ii), the complete s ets of c(ij) and s(ij) were obtained. This approach avoids the trouble some, error-prone determination of off-diagonal c(ij)(s(ij)) by the us ual measurements along nonprincipal directions. The approach was appli ed to a boron-aluminum composite where the off-diagonal terms remain u ncertain. In principle, the approach applies to any orthorhombic-symme try material.