Session: DFMLC-05-01: Design for Additive Manufacturing

Paper Number: 116652

116652 - Applicability of Load Separation Method to Additively Manufactured Abs 

Material extrusion (ME) is an additive manufacturing (AM) process in which the molten material is disposed through a nozzle layer by layer. In recent years, polymer ME has been increasingly utilized for end-use load bearing applications. Because each layer is created by filament deposition, there are voids and air gaps between layers and welds that make the parts vulnerable to failure. Thus, understanding the fracture properties becomes critical for design and manufacturing of robust components. The fracture toughness of ductile materials is described in terms of J-integral, which evaluates the energy released per unit area of crack surface. In evaluating J-integral, a plastic work factor $\eta_{pl}$ is used, which is inferred experimentally. The values of $\eta_{pl}$ have been investigated for metals and conventionally manufactured ductile polymers. $\eta_{pl}$ is evaluated using load separation criterion, in which if valid, load is represented as a multiplication of two separate functions: crack geometry and material functions, respectively. Load separation parameter is the load ratio between two specimens with different crack length at same displacement.

This study investigated the applicability of the load separation parameter to single-edge notched bending ABS specimens. Blunt notched specimens with varying a/W ratios have been tested.

By fitting a power law, $\eta_{pl}$ was calculated and found to be in good agreement with the values for conventionally metals and polymers. Additionally, work factor for total displacement $\eta$ was also calculated and values were compared with $\eta_{pl}$.

Presenting Author: Astrit Imeri Tennessee Technological University

Presenting Author Biography: Astrit Imeri is a Ph.D. candidate in the department of Mechanical Engineering at Tennessee Technological University. He is currently working as a graduate research assistant for the Center for Manufacturing Research under Dr. Wilson. He holds degrees in Mechanical Engineering (M.S.) from Tennessee Technological University and (B.S.) from Middle East Technical University. His research interests are in additive manufacturing and mechanical behavior of materials. He is a member of SME and SAMPE.

Authors:

Astrit Imeri Tennessee Technological University
Christopher D. Wilson Tennessee Technological University