| Sandwich panels with cellular metals are multifunctional. They are utilized in ultra-light designs, in heat dissipation and for energy absorption. The benefits are topology-sensitive: that is, the important properties are sensitive to both the geometry of the sandwich panels and the micro-architecture of the cellular cores. Establishing relationships between prismatic core topology and performance is the major goal of this research. To realize this objective, the thesis is in four interrelated parts.; In Part I, ultra-light sandwich panels with prismatic cores are optimized for quasi-static load capacity at minimum weight by using elastic analysis and imposing load limits based on yielding and buckling. The optimization is performed in the two principal in-plane directions and jointly for both orientations. The designs emerging from joint optimizations have slightly lower load capacity than those optimized singly, but with the benefit of equal strengths in all in-plane directions.; In Part II, the quasi-static load capacity beyond the initial nonlinearity is characterized by means of a full nonlinear analysis that incorporates plastic hardening, post buckling and core/face contact. For corrugated structures, a study of buckling modes and their imperfection sensitivity is performed. For pyramidal truss cores, a constitutive law is utilized instead of 3D fully-meshed simulation. Comparisons between simulation and experiment are used to assess the fidelity of the constitutive law.; In Part III, the response to impulsive loads, especially to water blast, is investigated. The characterization is conducted by means of the constitutive law with strain-rate dependence. The law was assessed by comparison with two sets of experiments. Integration of Parts II and III affirms that the constitutive law approach is capable of predicting the overall performance.; Finally, in Part IV, a comprehensive study of multilayer corrugated panels is conducted, including quasi-static and dynamic measurements, 3D fully-meshed simulations, calibration of the constitutive law for large-scale simulations and analytic estimates. Such a study enables a thorough understanding of the performance of sandwich panels subject to a variety of loads, thereby providing a template for future research. |
