The effect of injection molding lunker defect on the durability performance of polymer gears

• Published in: International journal of mechanical sciences Vol. 180; p. 105665
• Main Authors: Lu, Zehua, Liu, Huaiju, Wei, Peitang, Zhu, Caichao, Xin, Dong, Shen, Yaqiang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.08.2020
• Subjects: Durability test; Fatigue lives; Injection molding lunker; Polymer gears; Tooth root fracture; Tooth root fracture; Polymer gears; Durability test; Injection molding lunker; Fatigue lives
• ISSN: 0020-7403; 1879-2162
• DOI: 10.1016/j.ijmecsci.2020.105665

•The injection molding lunker defect is detected by X-ray CT and the polymer gear fatigue model considering lunker is established considering the thermal-elastic-plastic constitutive behavior.•The effects of loading condition and the lunker defect on the POM gear fatigue life are studied numerically and experimentally.•The failure mode competitive mechanism of POM gears reveals that the final failure mode is more sensitive to the loading condition, but the presence of injection molding lunker rises the possibility of tooth root breakage. Polymer gears manufactured with injection molding have been widely used in many industries, but the unavoidable injection molding lunker defects limit the loading capacity and the further use of polymer gears in power transmissions. In this work, injection molding lunker defects are detected by X-ray CT and a polymer gear fatigue model with lunker defect is established considering the thermal-elastic-plastic constitutive material behavior. Durability tests are also conducted, and the fatigue lives correspond well with simulation results. Results reveal that the lunker defect jeopardizes the loading capacity of tooth root under medium or heavy loading conditions, while the tooth flank failure is significantly influenced by the loading condition. [Display omitted]