Experiments And FEM Analysis Of Cushioning Property Of Molded Pulp Products

Molded pulp package products are a kind of typical green cushioning material. Due to their favorable cushioning property, cheap price and recyclable environmental-protection advantage, the molded pulp package products are increasingly widely used in package domain. Molded pulp products are made form paper-kind packaging material and the research on its static and dynamic cushioning property under different environment humidity and the effect of humidity on the energy absorption characteristics will have great value on the molded pulp cushioning package design.In this paper, mechanical properties of molded pulp products under different humidity are researched through experimentations, the effect of humidity on the static and dynamic compression properties is found, the energy absorption diagram including humidity factor is estimated, and the effect of humidity on the cushioning property of molded pulped products is attributed. At the same time, simulation analyses on the static and dynamic compression of molded pulp products under different humidity are made by ANSYS/LS-DYNA. The method of numerical simulation can reduce the test cost and increase the structure design efficiency of the molded pulp products.In this paper, physical parameters of molded pulp material were tested under different humidity (RH=50%,70%,80% and 90%), such as thickness and density. According to GB/T 5258-2008, elastic modulus were gained by the compression test in the in-plane direction.According to GB 8168-87 Testing method of static compression for package cushioning materials and GB 8167-87 Testing method of dynamic compression for package cushioning materials, tests of static compression and dynamic compact were made to the molded pulp products under different humidity and stress-strain curves were plotted. Simulation analysis of these static compression tests and dynamic compact tests were made by ANSYS/LS-DYNA. A acceptable result is achieved between the theoretical and experimental results. Environmental humidity has an obvious influence on both the static and dynamic cushioning property. The cushioning property of the molded pulp products decreases greatly with the increase of the environmental humidity.In this paper, both the static compression and dynamic compaction energy absorption diagrams of the molded pulp products were plotted by MATLAB under different humidity conditions. From these diagrams, it can be seen obviously that the cushioning property of the molded pulp product decreases with the increase of the environmental humidity.The conclusions of this paper play an important role in improving the estimation technique of the molded pulp products cushioning properties and can be a convenient and effective guidance of the cushioning structural optimum design.This paper is funded by the national natural science foundation (50775100).