In this paper, a three-dimensional smooth particle hydrodynamics (SPH) simulator for modeling grain scale fluid flow in porous rock is presented. The versatility of the SPH method has driven its use in increasingly complex areas of flow analysis, including flows related to permeable rock for both groundwater and petroleum reservoir research. While previous approaches to such problems using SPH have involved the use of idealized pore geometries (cylinder/sphere packs etc), in this paper we detail the characterization of flow in models with geometries taken from 3D X-ray microtomographic imaging of actual porous rock; specifically 25.12 % porosity dolomite. This particular rock type has been well characterized experimentally and described in the literature, thus providing a practical ‘real world’ means of verification of SPH that will be key to its acceptance by industry as a viable alternative to traditional reservoir modeling tools. The true advantages of SPH are realized when adding the complexity of multiple fluid phases, however, the accuracy of SPH for single phase flow is, as yet, under developed in the literature and will be the primary focus of this paper. Flow in reservoir rock will typically occur in the range of low Reynolds numbers, making the enforcement of no-slip boundary conditions an important factor in simulation. To this end, we detail the development of a new, robust, and numerically efficient method for implementing no-slip boundary conditions in SPH that can handle the degree of complexity of boundary surfaces, characteristic of an actual permeable rock sample. A study of the effect of particle density is carried out and simulation results for absolute permeability are presented and compared to those from experimentation showing good agreement and validating the method for such applications.

In this study, various 3D printed metamaterials are investigated for application in energy absorbing structures in motorsports. Impact attenuating structures are used to decelerate vehicles and protect drivers in the event of a crash. Additive manufacturing enables complex plastic structures which can facilitate improved angular resistance and reduced weight and cost compared with traditional approaches. Metamaterials were 3D printed from PLA using commercially available equipment and include gyroid structures, a novel reinforced gyroid design and a lattice designed using finite-element analysis-based topology optimization. Compression testing was used to measure stress–strain response, compressive modulus, and energy absorption. This demonstrated gyroids and reinforced gyroids have ideal compressive behavior for high energy absorption under impact. The topology optimized metamaterial was found unsuitable for this application due to its high stiffness, revealing a weakness in traditional topology optimization approaches which are not catered to maximize energy absorption. The reinforced gyroid demonstrated the highest specific energy absorption and was used to manufacture an impact attenuator which demonstrated the potential to safely stop a hypothetical 300 kg vehicle crash. This work supports that gyroid-based structures can reduce weight, volume and cost over current materials in all motorsport categories, with improved safety from oblique crashes.