Direct numerical simulation of mechanical response in synthetic additively manufactured microstructures

Abstract

Additive manufacturing (AM) processes for metals can yield as-built microstructures that vary significantly from their cast or wrought counterparts. These microstructural variations can in turn, have profound effects on the properties of a component. Here, a modeling methodology is presented to investigate microstructurally-influenced mechanical response in additively manufactured structures via direct numeral simulation. Three-dimensional, synthetic voxelized microstructures are generated by kinetic Monte Carlo (kMC) additive manufacturing process simulations performed at four scan speeds to create a thin-wall cylindrical geometry notionally constructed using a concentric-pathed directed energy deposition AM process. The kMC simulations utilize a steady-state molten pool geometry that is held constant throughout the study. Resultant microstructures are mapped onto a highly-refined conformal finite-element mesh of a part geometry. A grain-scale anisotropic crystal elasticity model is then used to represent the constitutive response of each grain. The response of the structure subjected to relatively simple load conditions is studied in order to provide understanding of both the influence of AM processing on microstructure as well as the microstructure’s influence on the macroscale mechanical response.

Simulation Study of Hatch Spacing and Layer Thickness Effects on Microstructure in Laser Powder Bed Fusion Additive Manufacturing using a Texture-Aware Solidification Potts Model

“…The texture-aware solidification (TS) Potts model approach is derived from the classical grain growth Monte Carlo (MC) Potts model (Ref [24][25][26], and the use of Potts models for simulation of AM parts by Rodgers et al (Ref 27,28). The grain growth Potts model is an energy minimization approach that is able to accurately simulate curvature-driven grain growth (Ref 24).…”

Optimization of the Fluidic-Based Assembly for Three-Dimensional Construction of Multicellular Hydrogel Micro-Architecture in Mimicking Hepatic Lobule-like Tissues

“…Since the module is suspended in the ECMs in the initial state, it is very important to adjust the parameters of microflow on the module in order to have the module threaded through the microneedle accurately and quickly [ 24 , 25 ]. Figure 2 b indicates the force exerting on the module by microflow during the assembly process.…”

“…All of the above assembly methods do not have enough assembly force to guarantee the stability and consistency of each assembly process, and also cannot arrange microstructures spatially and cannot achieve collective assembly for anisotropic microstructures, leading to low assembly efficiency and increased failure rate. Although the physical push can provide larger force to manipulate the microstructures and keep them regularly on the microneedle, the physical push cannot flexibly adjust the contact force and the biomaterial to fabricate the microstructures are very fragile, easily damaged when the micromanipulator contacts to them [ 21 , 22 , 23 , 24 ]. Thus, a more efficient method to implement the fluidic-based assembly process is proposed.…”

Three-Dimensional Additively Manufactured Microstructures and Their Mechanical Properties

“…The method has been described extensively in previous publications, and the reader is referred to these works for further details. 13,[27][28][29] After the generation of stochastic volume elements (SVEs) with AM microstructures in SPPARKS, the SVEs were assigned a crystallographic texture. First, the ''uniformODF'' and ''fi-breODF'' functions of the MTEX MATLAB toolbox 30 were used to generate uniformly random and fiber orientation distribution functions.…”