Three-bay linear grillage – difference between FEM and ASEA energy level differences for BT model (source subsystem: B1): (a) FEM (uniform material properties) with Euler-Bernoulli elements; (b) FEM (random Young’s modulus) with Euler-Bernoulli elements; (c) FEM (uniform material properties) with Timoshenko elements; (d) FEM (random Young’s modulus) with Timoshenko elements. bending wave energy receiving subsystem; torsional wave energy receiving subsystem.