Foam made panels as efficient building elements are becoming a major role player in modular construction with a variety of applications worldwide. However, construction accuracy, technology, and method can have serious effects on the panels’ behavior. In this study, using a unique pneumatic pressure testing rig, bending tests are conducted on the two types of rigid polyurethane panels. The panels are categorized based on the existence of construction cold joints (seams) as S (Seamless) type and TS (Transverse Seams) type. The S type panels are tested under monotonic uniform loading with a maximum nominal pressure of about 1 atm as the witness specimens. The TS panels are tested under both monotonic and cyclic uniform loading, and the deflections-pressure behavior obtained. The results show that S panels could resist up to 0.77 atm under monotonic uniform loading, while the minimum tensile strength of the foam is 13 MPa. In addition, panels with transverse seams collapsed under monotonic and cyclic loads at an average of 0.46 atm and 0.33 atm respectively but at the same position, located on the seamed section, which represent the same failure mode. Based on the results, the seamed section exhibited a maximum tensile strength of about 33.1% of an intact section under monotonic loading; and 27.9% lower results under cyclic loading.

The investigation of dynamic response of intervertebral disc is beneficial for the development of new synthetic and engineered tissues for treating diseased or injured disc. There are limited experimental studies on comparing the effect of loading mode and rate on global response of intervertebral disc. In this study, in-vitro experiments were performed using a total of 24 porcine motion segments. The harvested specimens were assigned to prolong and 2 different cyclic loadings. Both disc deformations and water contents were measured to investigate how the mode and rate of loading affect the response of intervertebral disc. In parallel, a backward FE poroelastic model combined with in-vitro experiments were used to find the material properties of intervertebral discs. The experimental result showed that the final disc height loss under creep loading was significantly greater than cyclic groups. Increasing the frequency of cyclic loading decreased the disc height loss. The water content decreased significantly in cyclic loading from those in prolong loading. The backward FE models showed that, the elastic modulus of anulus fibrosus and nucleus pulposus were 2.43 (±0.48) MPa and 1.46 (±0.29) MPa, respectively. The hydraulic permeability was 2.08 (±0.42) ×10-16m4/Ns, and the Poisson’s ratio was 0.21 (±0.03). In conclusion, this study investigated how the loading mode and rate affect porcine intervertebral disc deformation. It is found that dynamic stiffness is greater at higher frequencies which resulted from interactions between the solid phase and fluid flow within the disc.