Fatigue Life Study Of Loop Die Basic On Biomass Pelletizing Mechanism

Biomass pelletizing technology can densify loose biomass, significantly improve the performance of biomass products as an effective way to use biomass energy. However, the short life of the key part—biomass loop-die becomes the constraint of the biomass pelletizing development, so it is significant to study the biomass pelletizing technology and the fatigue life of the loop-die.The biomass pelletizing mechanism is studied. Its micro-mechanism is built first in this article, especially the key mathematical model—the mechanical contact geometry model of biomass pelletizing from macro to micro is built. It shows the positive pressure F is proportional to the cosine of the particle surface angle ai.In the study, the elastic-plastic mechanics, contact mechanics and visco-elasticity theory are built. The simulation of the biomass pelletizing process is taken with finite element software-ANSYS, using Euler method, in the simulation, its contact finite element model is built, and its stress and rheological characters, while equivalent stress and friction distribution of loop die is analyzed. The correctness of the pelletizing micro-mechanism is proved, and it is the base of life analysis of loop die.The life of the biomass pelletizing loop-die is studied using finite element method, and it provides a new method to study loop-die life. Considering failure forms, failure mechanism, and factors referring life of the loop-die, its life is analyzed. Basic on the material fatigue life experimental data, using the Weibull formula the S-N curve of loop-die is built. While the fatigue damage accumulation principle—Palmgren-Miner principle is built. COSMOSWorks software is used to analyze the fatigue life of loop-die with different structural parameters, using rain-flow counting method in the process.The results show that hole shape, hole diameter, hole aspect ratio, hole distribution, and hole number affect an important effect on loop-die life. The life of hole alternating rows loop-die is longer than the parallel; the elliptical hole loop-die's life is longer than the circle, and its intensity ratio is about 3:2; but limited to the difficulties of an elliptical hole manufacturing processes, the fatigue analysis method is used to analyze the life of loop-die with 720 circle,10mm diameter,5:1 aspect ratio, alternating rows holes, which verifies the finite element fatigue analysis correct.