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In this paper, dynamic impact between cellular shear-band-based non-pneumatic tire and sand with obstacle is investigated by using the Finite Element Method (FEM) for the NASA's new Moon mission. In this research, the shear band with cellular geometry of (cell angle θ = -65°, cell height h = 21) is used. The Lebanon sand found in New Hampshire is used in this research and Drucker-Prager/Cap plasticity constitutive law with hardening is employed to describe the behavior of the sand. The obstacle is represented as an elastic body. Penalty contact algorithm is used to model the tangential behavior of the contact between the tire and sand. Coulomb's law is considered for the friction between tire and sand. Numerical results show the deformation of sand and tire. The effects of the running speed on the deformation of tire and sand, stresses and strains of the tire and sand, vertical accelerations of the hub center, horizontal reaction forces of the hub center are presented.

In this paper, the Finite Element Method (FEM) is used to investigate the tread profile effects on the performance of the cellular shear band-based non-pneumatic tire when interacting with sand for the NASA's new Moon mission. This non-pneumatic tire consists of three major components: a critical cellular shear band, two inextensible circumferential membranes, and a group of deformable spokes. The cellular shear bands made of an aluminum alloy (AL7075-T6), are designed to have the same effective shear modulus of 6.5E+6 Pa. In this research, the shear band with cellular geometry of (θ = -65°, h = 21) is used. The Lebanon sand found in New Hampshire is used in this research and Drucker-Prager/Cap plasticity constitutive law with hardening is employed to describe the behavior of the sand. The tire and treads with different profiles are treated as deformable elastic bodies.

In this paper, the Finite Element Method (FEM) is used to model and simulate the dynamic interaction between non-pneumatic tire and sand with obstacle to investigate the influence of obstacle on performance of the non-pneumatic tire. The non-pneumatic tire consists of three major components: two inextensible circumferential membranes, a critical shear beam, and a group of deformable spokes. The non-pneumatic tire fabricated of segmented cylinders is illustrated and the FEM model for the tire is given in detail. The tire is treated as an elastic deformable body with the inertia effect included. Lebanon sand found in New Hampshire is used in this simulation because of the availability of a complete set of material properties in the literature. Modified Drucker-Prager/Cap plasticity constitutive law with hardening is utilized to model the sand. The obstacle is represented as an elastic body.

Recent research at Clemson University has focused on the development of an advanced non-pneumatic, non-elastomeric lunar wheel for NASA with superior traction. This paper reports on several concepts for tread materials and geometries that have been explored for tire-on-sand use. Specifically, fourteen concepts, involving the use of metal meshes, textile carpet materials, soft grousers, foams, and screens, were physically tested in an on-vehicle environment. Prototypes for each concept and formal test procedures to quantify traction were developed. This paper presents the results of the tests for several different concepts and the comparison between the concepts that were developed. Students developed their own testing environment through which these test procedures are implemented, an inclined hill 45 ft. in length and 8 ft. wide will approximately 6 inches deep filled with sand.

To facilitate the design of a non-pneumatic tire for NASA's new Moon mission, the authors used the Finite Element Method (FEM) to investigate the interaction between soil and non-pneumatic tire made of different cellular shear bands. Cellular shear bands, made of an aluminum alloy (AL7075-T6), are designed to have the same effective shear modulus of 6.5E+6 Pa, which is the shear modulus of an elastomer. The Lebanon sand of New Hampshire is used in the model. This sand has a complete set of material properties in the literature and Drucker-Prager/Cap plasticity constitutive law with hardening is employed to model the sand. The tires are treated as deformable bodies, and the authors used the penalty contact algorithm to model the tangential behavior of the contact. The friction between tire and sand is considered by using Coulomb's law. Numerical results show deformation of sand and tire.

This research examines a Discrete Element Method (DEM) for modeling the behavior of sand under various loading conditions as a critical first step in developing computational tools to aid in designing new sand-tire interaction systems for improved traction and mobility. Sand as a material is challenging to model computationally due to its unusual behavior: sometimes resembling a fluid and sometimes behaving more like a solid, yet never exactly replicating either. This behavior arises from the particulate nature of sand which, in contrast to the systems typically modeled in continuum mechanics, is not readily represented by continuum models. In sand, elements (i.e. particles) do not have permanent associations with neighboring elements as they do in most continua, but rather are free to migrate anywhere in the domain according to their interactions with other elements.

In this paper, in support of developing an advanced non-pneumatic lunar tire, a dynamic interaction model between non-pneumatic tire and sand is presented using the Finite Element Method (FEM). This non-pneumatic tire is composed of three major components: a critical shear beam, two inextensible circumferential membranes, and deformable spokes. The non-pneumatic tire made of segmented cylinders is described in detail. The tire is treated as an elastic deformable body with the inertia effect is included. Lebanon sand found in New Hampshire is modeled as because of the availability of a complete set of material properties in the literature. The Drucker-Prager/Cap plasticity constitutive law with hardening is employed to model the sand. Numerical results show contact pressure distribution, distributions of various stresses and strains, deformation of non-pneumatic tire, and deformation of sand.