Mechanical Properties Of Metallic Hollow Sphere Material Component And Structural Design

The development of industrial technology, communication, transportation and scientific & technical aerospace require development of lighter, stiffer, stronger and tougher structural materials and its preparation method. Metallic hollow sphere structural material is a type of the super-light cellular metallic material. Studies on the mechanical properties of single sphere and multi-sphere components are important work for the studies of mechanical behavior and form design of whole metallic hollow sphere cellular material. In this paper, the theoretic, experimental and numerical studies of mechanical properties of single sphere, multi-spheres component and metallic hollow sphere composite were carried out.In this paper, the mechanical properties of single sphere shell compressed between two rigid plates were studied. The theoretic critical force of thin-wall sphere shell under compression and the nominal stress-strain relationship of medium thick-walled sphere under compression were derived respectively. The dividing limit different from traditional theory of relative thickness of sphere shell was provided.Then, a series of quasi-static compressive experiments of thin-walled spheres and medium thick-walled spheres welded with two hemispheres were conducted. The deformation behaviors of it were observed, and its critical force of buckling or yield limit, Young's modulus and effective stress-strain curves were obtained. And the influence of the change of angle between welding line and horizontal line was analyzed. The influence of cracks produced by welding was analyzed too.The mechanical properties of multi-spheres components are the basic reference for the design of metallic hollow sphere materials. In this paper, many packing models of multi-spheres components were devised and its quasi-static compressive experiments were carried out. The buckling or collapse behavior were observed and analyzed, and its load-displacement curves and effective stress-strain curves were obtained. The buckling or yield limit, effective elastic modulus, specific stiffness and specific energy absorb were discussed, and the optimal packing model was provided.Epoxy filled with one or many thin-walled metallic hollow spheres is a new style composite, and its quasi-static compressive experiments were conducted. The compressive experiments of epoxy and syntactic foam were also conducted for the comparative analysis. The yield limit and effective elastic modulus were discussed. Then, the numerical simulations of composite with three types of packing models were conducted by considering of the change of shell thick. The change laws of effective elastic modulus and effective Poisson's ratio were discussed, and an optimal packing model of metallic hollow spheres in composite was provided.To analyse the laws, the numerical simulations of half sphere shells were conducted by changing the thick and radius of shell. The critical thick of buckling was gained and the deformation behavior agreed with the experiment. Then, the numerical simulations of multi-spheres components with three types of packing models were conducted too, and its effective yield limit and elastic modulus were provided. The mechanical behavior of the three types of packing models was analyzed.Finally, many type forms of metallic hollow sphere structure were provided. The laws of collapse in the process of compression were forecasted. And the reasonable structural designs for the actual applications were presented.