Figure 6.

The mechanical response characteristics of foam materials in quasi-static experiments under a strain rate of 10⁻³ s⁻¹: (a) The diagram of the force and the displacement of foam materials as a function of the time, r₁ is the linear phase, r₂ is the plateau phase, and r₃ is the density phase, the orange line represents the force of the specimen, and the blue line represents the compression displacement of the specimen. Moreover, the whole deformation process of foam exhibited the linear phase, the plateau phase, and the density phase, respectively; (b) the diagram of the stress of the foam as a function of the strain, the yield stress σ₀ is 0.00998 MPa, the locking stress σ_L is 0.27 MPa, and the locking strain ε_L is 0.78.