Congratulations Osama! His 2nd paper “A Self-Organizing Evolutionary Method to Model and Optimize Correlated Multiresponse Metrics for Additive Manufacturing Processes” was accepted for publication in ASTM Journal of Smart and Sustainable Manufacturing Systems. Here is the abstract:

A Self-Organizing Evolutionary Method to Model and Optimize Correlated Multiresponse Metrics for Additive Manufacturing Processes

Osama Aljarrah¹, Jun Li^1*, Wenzhen Huang¹, Alfa Heryudono², and Jing Bi³

1. Department of Mechanical Engineering, University of Massachusetts Dartmouth, Dartmouth, MA 02747

2. Department of Mathematics, University of Massachusetts Dartmouth, Dartmouth, MA 02747

3. Dassault Systemes SIMULIA Corp, Johnston, RI 02919

The use of robust multi-response constrained optimization techniques, where multiple objective responses are involved, is becoming a crucial part in additive manufacturing (AM) processes. Common and popular techniques, in most cases, rely on the assumption of independent responses. In practice, however, many of the desired quality characteristics can be correlated. In this work, we propose a technique based on three ingredients: hybrid self-organizing (HSO) method, desirability function (DF), and evolutionary algorithms (EA) to analyze, model and optimize the multiple correlated responses for the fused deposition modeling (FDM) process, one of the most popular AM technologies. The multi-objective functions are formulated by employing the HSO method and DF, where structural integrity, and process efficiency metrics are considered for the data-driven correlated multi-response models. Subsequently, layer thickness, nozzle temperature, printing speed, and raster angles are taken as process parameters (decision variables). The operational settings and capabilities for the FDM machine are defined as boundary constraints. Different EA algorithms, the non-dominated sorting genetic algorithm (NSGA-II) and the multi-objective particle swarm optimization (MOPSO) method, are then deployed to model the AM criteria accordingly to extract the Pareto-front curve for the correlated multi-response functions. FDM experimental design and data collection for the proposed method are provided and used to validate our approach. This study sheds light on formulating robust and efficient data-driven modeling and optimizations for additive manufacturing processes.

 

Congratulations Rojin! Her paper “Extended finite element method (XFEM) modeling of fracture in additively manufactured polymers” was accepted for publication in the journal of Additive Manufacturing. Here is the abstract (the paper link):

Extended finite element method (XFEM) modeling of fracture in additively manufactured polymers

R. Ghandriz¹, K. Hart², J. Li^1*

¹Department of Mechanical Engineering, University of Massachusetts, Dartmouth, MA 02747

² Milwaukee School of Engineering, Milwaukee, WI 53202

The fracture of additively manufactured polymer materials with various layer orientations is studied using the extended finite element method (XFEM) in an anisotropic cohesive zone model (CZM). The single edge notched bending (SENB) specimens made of acrylonitrile-butadiene-styrene (ABS) materials through fused filament fabrications with various crack tip/layer orientations are considered. The XFEM coupled with anisotropic CZM is employed to model the brittle fracture (fracture between layers), ductile fracture (fracture through layers), as well as kinked fracture behaviors of ABS specimens printed with vertical, horizontal, and oblique layer orientations, respectively. Both elastic and elastoplastic fracture models, coupled with linear or exponential traction-separation laws, are developed for the inter-layer and cross-layer fracture, respectively. For mixed inter-/cross- layer fracture, an anisotropic cohesive zone model is developed to predict the kinked crack propagations. Two crack initiation and evolution criteria are defined to include both crack propagation between layers (weak plane failure) and crack penetration through layers (maximum principal stress failure) that jointly determine the zig-zag crack growth paths. The anisotropic cohesive zone model with XFEM developed in this study is able to capture different fracture behaviors of additively manufactured ABS samples with different layer orientations.