Band diagrams of auxetic-like metamaterials generated with elementary cells (10 m × 10 m × 10 m) with bars (concrete) making an angle (a) α = 0°; (b) α = 30°; (c) α = 45°; (d) α = 60° where the horizontal axis is the normalized k wavevector describing the edges of the irreducible Brillouin zone ΓXMR and the vertical axis is the frequency (Hz). Green curves correspond to shear and pressure waves propagating in homogeneous isotropic bulk (concrete). Shaded regions mark the location of complete (dark gray) and partial (light gray) stop bands.