scholarly journals Using Additive Manufacturing and Finite Element Analysis in a Design-Analyze-Build-Test Project

2015 ◽  
Author(s):  
William Howard ◽  
Rick Williams ◽  
Sarah Gurganus
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Additive Manufacturing ◽  
Element Analysis ◽  
Test Project

scholarly journals Finite Element Analysis on Initial Crack Site of Porous Structure Fabricated by Electron Beam Additive Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7467
Author(s):  
Meng-Hsiu Tsai ◽  
Chia-Ming Yang ◽  
Yu-Xuan Hung ◽  
Chao-Yong Jheng ◽  
Yen-Ju Chen ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Mechanical Strength ◽  
Deformation Behavior ◽  
Initial Crack ◽  
Elastic Model ◽  
Element Analysis ◽  
Strength And Deformation

Ti6Al4V specimens with porous structures can be fabricated by additive manufacturing to obtain the desired Young’s modulus. Their mechanical strength and deformation behavior can be evaluated using finite element analysis (FEA), with various models and simulation methodologies described in the existing literature. Most studies focused on the evaluation accuracy of the mechanical strength and deformation behavior using complex models. This study presents a simple elastic model for brittle specimens followed by an electron beam additive manufacturing (EBAM) process to predict the initial crack site and threshold of applied stress related to the failure of cubic unit lattice structures. Six cubic lattice specimens with different porosities were fabricated by EBAM, and compression tests were performed and compared to the FEA results. In this study, two different types of deformation behavior were observed in the specimens with low and high porosities. The adopted elastic model and the threshold of applied stress calculated via FEA showed good capabilities for predicting the initial crack sites of these specimens. The methodology presented in this study should provide a simple yet accurate method to predict the fracture initiation of porous structure parts.

A Graph Theoretic Approach for Near Real-Time Prediction of Part-Level Thermal History in Metal Additive Manufacturing Processes

2019 ◽  
Author(s):  
Reza Yavari ◽  
Kevin D. Cole ◽  
Prahalad Rao
Keyword(s):  
Finite Element Analysis ◽  
Heat Flux ◽  
Finite Element ◽  
Graph Theory ◽  
Additive Manufacturing ◽  
Layer By Layer ◽  
Theory Approach ◽  
Element Analysis ◽  
Part Quality ◽  
Am Processes

Abstract The goal of this work is to predict the effect of part geometry and process parameters on the instantaneous spatial distribution of heat, called the heat flux or thermal history, in metal parts as they are being built layer-by-layer using additive manufacturing (AM) processes. In pursuit of this goal, the objective of this work is to develop and verify a graph theory-based approach for predicting the heat flux in metal AM parts. This objective is consequential to overcome the current poor process consistency and part quality in AM. One of the main reasons for poor part quality in metal AM processes is ascribed to the heat flux in the part. For instance, constrained heat flux because of ill-considered part design leads to defects, such as warping and thermal stress-induced cracking. Existing non-proprietary approaches to predict the heat flux in AM at the part-level predominantly use mesh-based finite element analyses that are computationally tortuous — the simulation of a few layers typically requires several hours, if not days. Hence, to alleviate these challenges in metal AM processes, there is a need for efficient computational thermal models to predict the heat flux, and thereby guide part design and selection of process parameters instead of expensive empirical testing. Compared to finite element analysis techniques, the proposed mesh-free graph theory-based approach facilitates layer-by-layer simulation of the heat flux within a few minutes on a desktop computer. To explore these assertions we conducted the following two studies: (1) comparing the heat diffusion trends predicted using the graph theory approach, with finite element analysis and analytical heat transfer calculations based on Green’s functions for an elementary cuboid geometry which is subjected to an impulse heat input in a certain part of its volume, and (2) simulating the layer-by-layer deposition of three part geometries in a laser powder bed fusion metal AM process with: (a) Goldak’s moving heat source finite element method, (b) the proposed graph theory approach, and (c) further comparing the heat flux predictions from the last two approaches with a commercial solution. From the first study we report that the heat flux trend approximated by the graph theory approach is found to be accurate within 5% of the Green’s functions-based analytical solution (in terms of the symmetric mean absolute percentage error). Results from the second study show that the heat flux trends predicted for the AM parts using graph theory approach agrees with finite element analysis with error less than 15%. More pertinently, the computational time for predicting the heat flux was significantly reduced with graph theory, for instance, in one of the AM case studies the time taken to predict the heat flux in a part was less than 3 minutes using the graph theory approach compared to over 3 hours with finite element analysis. While this paper is restricted to theoretical development and verification of the graph theory approach for heat flux prediction, our forthcoming research will focus on experimental validation through in-process sensor-based heat flux measurements.

scholarly journals Stiff isotropic lattices beyond the Maxwell criterion

2019 ◽  
Vol 5 (9) ◽  
pp. eaaw1937 ◽  
Author(s):  
Wen Chen ◽  
Seth Watts ◽  
Julie A. Jackson ◽  
William L. Smith ◽  
Daniel A. Tortorelli ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Topology Optimization ◽  
Additive Manufacturing ◽  
De Novo ◽  
Mechanical Stiffness ◽  
Element Analysis ◽  
Anisotropic Lattices ◽  
Design Materials

Materials with a stochastic microstructure, like foams, typically exhibit low mechanical stiffness, whereas lattices with a designed microarchitecture often show notably improved stiffness. These periodic architected materials have previously been designed by rule, using the Maxwell criterion to ensure that their deformation is dominated by the stretching of their struts. Classical designs following this rule tend to be anisotropic, with stiffness depending on the load orientation, but recently, isotropic designs have been reported by superimposing complementary anisotropic lattices. We have designed stiff isotropic lattices de novo with topology optimization, an approach based on continuum finite element analysis. Here, we present results of experiments on these lattices, fabricated by additive manufacturing, that validate predictions of their performance and demonstrate that they are as efficient as those designed by rule, despite appearing to violate the Maxwell criterion. These findings highlight the enhanced potential of topology optimization to design materials with unprecedented properties.

scholarly journals Hybrid Additive Manufacturing of Collector Coins

2020 ◽  
Vol 4 (4) ◽  
pp. 115
Author(s):  
João P. M. Pragana ◽  
Stephan Rosenthal ◽  
Ivo M. F. Bragança ◽  
Carlos M. A. Silva ◽  
A. Erman Tekkaya ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stainless Steel ◽  
Additive Manufacturing ◽  
Metal Cutting ◽  
Geometric Features ◽  
Aisi 316L ◽  
Element Analysis ◽  
Steel Aisi ◽  
Stainless Steel Aisi

The objective of this paper is to present a new hybrid additive manufacturing route for fabricating collector coins with complex, intricate contoured holes. The new manufacturing route combines metal deposition by additive manufacturing with metal cutting and forming, and its application is illustrated with an example consisting of a prototype coin made from stainless steel AISI 316L. Experimentation and finite element analysis of the coin minting operation with the in-house computer program i-form show that the blanks produced by additive manufacturing and metal cutting can withstand the high compressive pressures that are attained during the embossing and impressing of lettering and other reliefs on the coin surfaces. The presentation allows concluding that hybrid additive manufacturing opens the way to the production of innovative collector coins with geometric features that are radically different from those that are currently available in the market.

scholarly journals Compressive Behaviour of Lattice Structures Manufactured by Polyjet Technologies

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2767
Author(s):  
Camil Lancea ◽  
Ian Campbell ◽  
Lucia-Antoneta Chicos ◽  
Sebastian-Marian Zaharia
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Compressive Strength ◽  
Additive Manufacturing ◽  
Critical Section ◽  
Test Machine ◽  
Lattice Structures ◽  
Element Analysis ◽  
Different Types ◽  
Fea Analysis

Additive manufacturing (AM) techniques can help to reduce the time and cost for manufacturing complex shaped parts. The main goal of this research was to determine the best strength structure of six different types of lattice cells, manufactured using the Poly Jet AM technology. In order to perform the tests, six samples with the same structure were created for each lattice type. For testing the samples in compression, an electromechanical test machine was used. finite element analysis (FEA) analysis was used in order to determine the area where the greatest stresses occured and to estimate the maximal compressive strength. The strongest structure was determined by obtaining the maximal compressive strength. This was calculated in two ways: as a ratio between the maximal supported force and the mass of the sample (N/g) and as a ratio between the maximal supported force and the critical section of the sample (MPa).

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