Essential Mechanical Properties And Constitutive Relation Of Metal Foam

Metal foam has many advantages which are superior to those of traditional metal and polymer foam. It has the properties of both functional material and structural material. And it is a new-style material with great potential.By combining experimental study with theoretical analysis, the tensile mechanical properties and constitutive relation of metal foam are studied. The major contents are followed by these:The development, manufacturing techniques, characteristic and application of metal foam are introduced briefly.The structure and morphology of metal foam are introduced. Several parameters that are used to evaluate the structure of metal foam are given, and effect of these parameters (relative density mainly) on the mechanical properties of foam material are also analyzed. In addition, the essential mechanical properties of metal foam are introduced briefly. A series of quasi-static state tensile tests on open-cell nickel foam which is manufactured in electrodeposition process are conducted. Based on the experimental results, effects of relative density, strain rate and temperature on the tensile mechanical properties of nickel foam are analyzed. It shows that density greatly affects the mechanical properties of nickel foam, and its elastic modulus, yield strength and tensile strength increase with increasing density; Under the condition of this experiment (quasi-static state), strain rate does not show notable effect on mechanical propertiesï¼› The mechanical properties of nickel foam show strongly temperature dependence, and its elastic modulus, yield strength and tensile strength decrease with increasing temperature. Expressions of mechanical properties (modulus and strength) of nickel foam, varying with relative density, temperature and strain rate are given. The tendency of theoretical prediction and experimental result coincide well.A method of establishing the macroscopic phenomenological constitutive model of metal foam is introduced. And a tensile constitutive relation of nickel foam containing strain rate and temperature is raised.