Sheikh Sharif Ahmed

• Doctor of Philosophy
• University of California, Davis

Isolating the effects of individual particle properties (e.g. shape, size, mineralogy, surface roughness) on the mechanical behavior of naturally occurring coarse-grained soils is a significant challenge in experimental studies. This challenge can be addressed by recent advances in 3D printing technology which enable generation of artificial sand-s...

Different particle properties, such as shape, size, surface roughness, and constituent material stiffness, affect the mechanical behavior of coarse-grained soils. Systematic investigation of the individual effects of these properties requires careful control over other properties, which is a pervasive challenge in investigations with natural soils....

Systematic investigation of the effects of individual particle properties, such as shape, size, surface roughness, and constituent materials stiffness, on the behavior of coarse-grained soils requires careful control over the other particle properties. Achieving this control is a pervasive challenge in investigations with naturally occurring soils....

This paper presents the prospect of 3D printing technology to generate artificial soil analogs with the goal of modeling the mechanical behavior of coarse-grained soils. 3D X-ray CT scans of natural angular and rounded sand particles have been used to generate angular and rounded particle analogs using the polyjet 3D printing technology. A comparis...

Three-dimensional finite element (FE) analysis of axial–vertical interaction behavior of buried pipelines in dense sand is performed. The commercially available FE software package Abaqus/Explicit is used to accommodate large displacement and to avoid convergence problems. In addition, a user subroutine is utilized to capture the pressure dependent...

This paper presents the initial developments of a framework for modeling the compression behavior of coarse-grained soil using 3D printed particle analogs. This framework consists of a newly developed normalization scheme for 1-D compression response based on Hertz contact theory. The scheme normalizes the differences in stiffness of the natural an...

The use of supplementary cementitious materials (SCMs) in concrete has increased worldwide because of their economic and environmental benefits. Supplementary cementitious materials include silica fume (SF), blast furnace slag (BFS), fly ash (FA) and rice husk ash (RHA), which are generally derived from industrial byproducts and agro-wastes and can...

The terrorist attacks and dangers by bomb blast have turned into an emerging issue throughout the world and the protection of the people and structures against terrorist acts depends on the prediction of the response of structures under blast and shock load. In this paper, behavior of aluminum and unidirectionally reinforced E-Glass Epoxy composite...

Three-dimensional finite element (FE) analysis of axial-vertical interaction behavior of buried pipelines with dense sand is performed. Commercially available FE software package Abaqus/Explicit is used to accommodate large displacement and to avoid convergence problems. In addition, a user subroutine is utilized to capture the pressure dependent s...

Large-diameter monopiles are widely used foundations for offshore wind turbines. In the present study, three-dimensional finite-element (FE) analyses are performed to estimate the static lateral load-carrying capacity of monopiles in dense sand subjected to eccentric loading. A modified Mohr–Coulomb (MMC) model that considers prepeak hardening, pos...

Three-dimensional finite element (FE) analyses are conducted to calculate the pullout capacity of a suction caisson subjected to oblique loadings. Two sets of FE analyses are performed using Abaqus FE software. In the first set, the sand around the caisson is modeled using the built-in Mohr Coulomb (MC) model available in Abaqus where constant valu...

With increasing demand of energy, attention to the alternative sources of sustainable energy is getting priority over the last decades. Offshore wind turbine is one of them. The most widely used foundation system for the wind turbine is the monopile, which is a large diameter single pile. In the present study, three-dimensional finite element (FE)...

Suction caissons are widely used in mooring systems for deep water oil and gas development projects. The response of a caisson in sand is different from its response in clay under pullout force. In this study, three-dimensional finite element (FE) analyses are conducted to calculate the pullout capacity of a suction caisson subjected to various obl...