Abstract

To study the three-dimensional strength characteristics of rockfill material under an anisotropic state, the anisotropic state variables were introduced into the Mohr-Coulomb failure criterion, and the failure criterion describing the three-dimensional strength of rockfill which was obtained in linear form in this paper. The anisotropic state variables were established with the fabric of rockfill particles. Based on the experimental results of a large triaxial consolidated drained test, fractal dimension theory was introduced to study the relationship between strength and deformation characteristics under different gradation and confining pressures. The experimental results and simulation have shown that: (1) The fractal theory can be used to quantitatively describe the rockfill particles crushing with all kinds of grades under different stress levels. (2) The fabric of rockfill particles was closely related to the three-dimensional strength characteristics. (3) The anisotropic state variables can describe the three-dimensional strength characteristics of rockfill well from a microscopic perspective.

Abstract

The development and construction of multilayered, high-strength membranes for large-scale inflatable structures requires understanding each layer's mechanical behavior. A typical multilayer configuration comprises a thin inner fabric layer that contains the inflation and pressurization fluid, air, or water, an intermediate fabric layer that protects the inner layer, and an external macro-fabric layer that provides mechanical strength to withstand membranal stresses resulting from the pressurization, as well as the effects of potential external forces. This macro-fabric usually comprises high-strength webbings interlaced in a plain weave pattern linked to the two inner layers at discrete connecting points. Previous experimental studies using a "picture frame" configuration have been dedicated to evaluating shear behavior to account for the drapeability of the inflatable necessary to conform to the irregularities when deployed in confined environments. While experimental evaluations provided valuable information on the shear properties of woven webbings, only a few configurations can be evaluated. This study focuses on developing a finite element simulation of the in-plane shear behavior of woven webbings manufactured with Vectran fibers. A three-dimensional simulation model is created with Simulia/Abaqus following the "picture frame" test configuration designed to produce an in-plane shearing effect from an axial force. The simulation model includes contact interactions, friction, biaxial pre-tensioning loads, and shearing effect implemented experimentally. A series of parametric studies is also conducted to assess the influence of changes in the pretension level and friction on the shear stress as a function of the angular distortion. Numerical results are compared with experimental evaluations, providing valuable insight into the shear behavior of macro-fabrics created from woven webbings.