Investigating inter/intralayer interface-triggered toughening mechanisms of three-dimensional printed polylactic acid using double-notch four-point-bending method. (19th May 2023)

• Record Type: Journal Article
• Authors: Chen, Kang; Zhu, Zhongmeng; Yang, Zhuoran; Xia, Yan; Sun, Yuzhou; Liu, Tianyuan; Cheng, Qian; Yao, Chengbin; Jiang, Han
• Is Part Of: Engineering fracture mechanics. Volume 284(2023)
• Publication Date: 2023-05-19
• Subjects: Material extrusion -- Fracture behavior -- Toughening mechanism -- Interfacial performance; Fracture mechanics -- Periodicals; Rupture, Mécanique de la -- Périodiques; Fracture mechanics; Periodicals; 620.112605
• DOI: 10.1016/j.engfracmech.2023.109277
• Languages: English
• ISSNs: 0013-7944

Abstract

Highlights: Deformation mechanism of the crack initiation zone is clarified. Effect of the interfacial strength on the toughening mechanism is discussed. High interfacial strength inhibits the interface-triggered toughening mechanism. DN-4PB method is applicable in studying 3D printed materials' toughening mechanism. Abstract: Three-dimensional (3D) printing technology is widely adopted in smart manufacturing, automotive, and aerospace fields for manufacturing complex geometric structures. Understanding the inter/intralayer interface-triggered toughening mechanisms of the 3D printed polylactic acid (PLA) materials produced by material extrusion is crucial. The fracture performance of the printed specimens in different fracture directions is evaluated with the single-edge-notch three-point-bending (SEN-3PB) test. Based on the double-notch four-point-bending (DN-4PB) method, the deformation mechanism around the crack tip and the crack propagation in the damage zone are systematically analyzed. It is clarified that the geometrical arrangement between the pre-crack and inter/intralayer and the interface bonding strength play decisive roles during the fracture process. The crack deflection, crack branching, and plastic deformation of the filaments are the main toughening mechanisms which endow 3D printed materials with better fracture performance than injection molded ones. However, the crack deflection and crack blunting could be inhibited if the intralayer interfacial bonding strength is excessively high. The results provide a good insight into the toughening mechanisms provoked by the inter/interlayer interface and could guide the design of the 3D printed specimens with optimized fracture performance.