scholarly journals Computational Design of Gradient Paths in Additively Manufactured Functionally Graded Materials

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Tanner Kirk ◽  
Edgar Galvan ◽  
Richard Malak ◽  
Raymundo Arroyave
Keyword(s):  
Functionally Graded Materials ◽  
Computational Design ◽  
Functionally Graded ◽  
Future Research ◽  
Graded Materials ◽  
316 L Stainless Steel ◽  
And Performance ◽  
Cr System ◽  
Parameter Dependency ◽  
Stainless Steel 316

Additive manufacturing (AM) has enabled the creation of a near infinite set of functionally graded materials (FGMs). One limitation on the manufacturability and usefulness of these materials is the presence of undesirable phases along the gradient path. For example, such phases may increase brittleness, diminish corrosion resistance, or severely compromise the printability of the part altogether. In the current work, a design methodology is proposed to plan an FGM gradient path for any number of elements that avoids undesirable phases at a range of temperatures. Gradient paths can also be optimized for a cost function. A case study is shown to demonstrate the effectiveness of the methodology in the Fe–Ni–Cr system. Paths were successfully planned from 316 L Stainless Steel (316 L SS) to pure Cr that either minimize path length or maximize separation from undesirable phases. Examinations on the stochastic variability, parameter dependency, and computational efficiency of the method are also presented. Several avenues of future research are proposed that could improve the manufacturability, utility, and performance of FGMs through gradient path design.

Applying Path Planning to the Design of Additively Manufactured Functionally Graded Materials

2018 ◽  
Author(s):  
Tanner Kirk ◽  
Richard Malak ◽  
Raymundo Arroyave
Keyword(s):  
Functionally Graded ◽  
Future Research ◽  
Graded Materials ◽  
Functionally Gradient ◽  
Path Design ◽  
And Performance ◽  
Cr System ◽  
Parameter Dependency ◽  
Infinite Set

Additive manufacturing has enabled the creation of a near infinite set of functionally gradient materials. One limitation on the manufacturability and usefulness of these materials is the presence of undesirable phases along the gradient path. For example, such phases may increase brittleness, diminish corrosion resistance, or severely compromise the printability of the part altogether. In the current work, a design methodology is proposed to plan an FGM gradient path for any number of elements that avoids undesirable phases at a range of temperatures. Gradient paths can also be optimized for a cost function. A case study is shown to demonstrate the effectiveness of the methodology in the Fe-Ni-Cr system. Paths were successfully planned from 316L SS to pure Cr that either minimize path length or maximize separation from undesirable phases. Examinations on the stochastic variability, parameter dependency, and computational efficiency of the method are also presented. Several avenues of future research are proposed that could improve the manufacturability, utility, and performance of FGMs through gradient path design.

Computational Design of Compositionally Graded Alloys for Property Monotonicity

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Tanner Kirk ◽  
Richard Malak ◽  
Raymundo Arroyave
Keyword(s):  
Cost Function ◽  
Functionally Graded Materials ◽  
Deposition Rate ◽  
Coefficient Of Thermal Expansion ◽  
Optimal Path ◽  
Computational Design ◽  
Functionally Graded ◽  
Function Parameter ◽  
Prior Work ◽  
Graded Materials

Abstract Functionally graded materials (FGMs) exhibit spatial gradients in properties that can be exploited to satisfy multiple conflicting performance objectives in the same part. Compositionally graded alloys are a subclass of FGMs that have received increased attention with the development of metal additive manufacturing. However, the formation of secondary phases can often lead to cracks or deleterious properties in these materials. In prior work, a computational methodology was presented that can design compositional gradients to avoid these phases at any temperature without the need to visualize phase diagrams (Kirk et al., 2018, “Computational Design of Gradient Paths in Additively Manufactured Functionally Graded Materials,” ASME J. Mech. Des., 140(11), p. 111410). The methodology optimizes gradient paths through composition space for a specified cost function, but prior work only considered minimizing path length or maximizing the distance from undesirable phases. In this work, a new cost function is presented to produce compositional paths with optimal property gradients. Specifically, monotonicity is presented as the optimal quality of a pathwise property gradient because monotonic property gradients can be transformed to nearly any form on the part by controlling deposition rate. The proposed cost function uses a metric for non-monotonicity to find the shortest path with monotonic properties and is shown to be compatible with optimal path planners. A synthetic case study examines the effect of a cost function parameter on the trade-off between length and monotonicity. The cost function is also demonstrated in the Fe-Co-Cr system to find a compositional path with monotonic gradients in coefficient of thermal expansion (CTE). The deposition of the path on a hypothetical part is then planned subject to a maximum deposition rate and CTE gradient. Future work is proposed to extend the framework to optimize multiple properties at once and to incorporate multi-material topology optimization (MMTO) techniques into a complete design methodology for functionally graded metal parts.

Dynamic Analysis with Stress Recovery for Functionally Graded Materials: Numerical Simulation and Experimental Benchmarking

2014 ◽  
Vol 2 (1) ◽  
pp. 21
Author(s):  
Carlos Alberto Dutra Fraga Filho ◽  
Fernando César Meira Menandro ◽  
Rivânia Hermógenes Paulino de Romero ◽  
Juan Sérgio Romero Saenz
Keyword(s):  
Numerical Simulation ◽  
Dynamic Analysis ◽  
Functionally Graded Materials ◽  
Functionally Graded ◽  
Stress Recovery ◽  
Graded Materials
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