Eur. Phys. J. E (2016) 39: 60
https://doi.org/10.1140/epje/i2016-16060-3

Regular Article

Effect of variable particle stiffness on force propagation and mechanical response of a composite granular material

¹ Key Laboratory of Mechanics on Disaster and Environment in Western China attached to the Ministry of Education of China, Lanzhou University, Gansu 730000, Lanzhou, PRC
² Department of Mechanics and Engineering Science, School of Civil Engineering and Mechanics, Lanzhou University, Gansu 730000, Lanzhou, PRC

^* e-mail: dmwang@lzu.edu.cn

Received: 8 March 2016
Revised: 8 May 2016
Accepted: 24 May 2016
Published online: 23 June 2016

Abstract

The force propagation and mechanical response are important for understanding the elasticity and deformation of a composite granular packings. In this paper, a 2D composite granular layers composed of particles with variable stiffness is proposed, and the effect of stiffness ratio between component particles on mechanical response is mainly considered. The results show that the decrease of stiffness ratio broadens the linear range of mechanical response and enhances the elasticity of the response in a composite granular system, showing a role similar with the friction in a monodisperse granular packings. Furthermore, a phase diagram for the crossover between a single-peaked and a double-peaked response is proposed, in which the critical stiffness ratio corresponding to the occurrence of the crossover decreases with the magnitude of external loading and increases with the friction. Finally, the microscopic mechanism of the crossover of the response is further discussed based on changes in contact network and force network.