【标题】Short-term Creep Behaviour of Different Polymers Used in Additive Manufacturing under Different Thermal and Loading Conditions
【参考中译】添加剂制造用不同聚合物在不同温度和载荷条件下的短期蠕变行为
【类型】 期刊
【关键词】 Additive manufacturing; Creep experiments; Polymer materials; Thermal effect
【参考中译】 添加剂制造；蠕变实验；聚合物材料；热效应
【作者】 Oguz Dogan
【摘要】 Polymer materials produced by additive manufacturing undergo significant changes In their dimensions under continuous loading conditions. This situation affects the operation of polymer structures produced by additive manufacturing within safe limits. Therefore, it is crucial to determine the creep behaviour of polymers produced by the additive manufacturing method. This study investigates the creep behaviour of six different materials, acrylonitrile butadiene styrene (ABS), chlorinated polyethylene (CPE), polylactic acid (PLA), tough polylactic acid (TPLA), polycarbonates (PC), and nylon most commonly used in additive manufacturing. The creep test specimens are firstly produced with a three-dimensional (3D) printer, and then their final dimensions are given using computer numerical control (CNC) milling. The creep experiments are carried out at three different ambient temperatures (25℃, 40℃, and 60℃) and two different stress levels (10 MPa, 20 MPa). According to the test results, it was determined that the material type, temperature, and loading levels significantly influenced the creep behaviour of the 3D printed polymer materials.
【参考中译】 由添加剂制造的聚合物材料在连续加载条件下其尺寸发生显著变化。这种情况会在安全范围内影响由添加剂制造产生的聚合物结构的运行。因此，确定由添加剂制造方法生产的聚合物的蠕变行为是至关重要的。本研究研究了六种不同材料的蠕变行为，它们是：丙烯腈-丁二烯-苯乙烯(ABS)、氯化聚乙烯(CPE)、聚乳酸(PLA)、韧性聚乳酸(TLA)、聚碳酸酯(PC)和尼龙(最常用于添加剂制造)。蠕变试验试件首先用三维(3D)打印机制作，然后用计算机数控(NC)铣削得到其最终尺寸。蠕变试验是在三种不同的环境温度(25℃、40℃和60℃)和两种不同的应力水平(10 Mpa、20 Mpa)下进行的。根据试验结果，确定了材料类型、温度和加载水平对3D打印聚合物材料的蠕变行为有显著影响。
【来源】 Journal of Mechanical Engineering 2022, vol.68, no.7/8
【入库时间】 2023/4/27
【标题】Deep learning-assisted real-time defect detection and closed-loop adjustment for additive manufacturing of continuous fiber-reinforced polymer composites
【参考中译】深度学习辅助的连续纤维增强聚合物复合材料添加剂制造的实时缺陷检测和闭环调整
【关键词】 Deep learning; Continuous fiber-reinforced composites; Defect detection; Additive manufacturing
【参考中译】 深度学习；连续纤维增强复合材料；缺陷检测；添加剂制造
【作者】 Lu Lu; Jie Hou; Shangqin Yuan; Xiling Yao; Yamin Li; Jihong Zhu
【摘要】 Real-time defect detection and closed-loop adjustment of additive manufacturing (AM) are essential to ensure the quality of as-fabricated products, especially for carbon fiber reinforced polymer (CFRP) composites via AM. Machine learning is typically limited to the application of online monitoring of AM systems due to a lack of accurate and accessible databases. In this work, a system is developed for real-time identification of defective regions, and closed-loop adjustment of process parameters for robot-based CFRP AM is validated. The main novelty is the development of a deep learning model for defect detection, classification, and evaluation in realtime with high accuracy. The proposed method is able to identify two types of CFRP defects (i.e., misalignment and abrasion). The combined deep learning with geometric analysis of the level of misalignment is applied to quantify the severity of individual defects. A deep learning approach is successfully developed for the online detection of defects, and the defects are effectively controlled by closed-loop adjustment of process parameters, which is never achievable in any conventional methods of composite fabrication.
【参考中译】 添加剂制造(AM)的实时缺陷检测和闭环调整是保证成品质量的关键，特别是碳纤维增强复合材料(CFRP)由于缺乏准确和可访问的数据库，机器学习通常仅限于AM系统的在线监控应用。本文开发了一套缺陷区域实时识别系统，并验证了机器人CFRP AM工艺参数的闭环调整。主要的新颖性是开发了一个深度学习模型，用于实时、高精度地检测、分类和评估缺陷。所提出的方法能够识别两种类型的CFRP缺陷(即错位和磨损)。将深度学习与错位程度的几何分析相结合，用于量化单个缺陷的严重程度。成功地开发了一种深度学习方法用于缺陷的在线检测，并通过对工艺参数的闭环调整来有效地控制缺陷，这在任何传统的复合材料制造方法中都是无法实现的。
【来源】 Robotics and Computer-Integrated Manufacturing 2023, vol.79
【标题】Structural analysis of compact heat exchanger samples fabricated by additive manufacturing
【参考中译】添加法制备紧凑型换热器试件的结构分析
【关键词】 Compact heat exchanger; 3D printing; Additive manufacturing
【参考中译】 紧凑型换热器；3D打印；添加剂制造
【作者】 G. Zilio; M. J. Teixeira; M. V. V. Mortean; F. G. Brandao; T. T. Pontin; J. L. G. Oliveira; K. V. Paiva
【摘要】 Compact heat exchangers are extensively employed in the industry due to their flexibility, geometric configuration characteristics, and the low ratio between heat transfer area by volume. Usually, these heat exchangers are exposed to high thermal and pressure gradients, which can cause structural failures during the operation. A new fabrication method employing additive manufacturing was evaluated to produce that equipment in this context. Twelve samples of 316L stainless steel that simulated a heat exchanger geometry were fabricated in two machines. A test rig was constructed for hydrostatic tests to evaluate their structural integrity through strain gauges. Some samples were submitted to pressures up to 700 bar without any leakage. The results show that printing orientation is crucial to the process, which influences material properties and, consequently, the von Mises stress observed. Properties on vertical orientation present lower stress levels. The influence of heat treatment was also verified, showing that machining processes locally alter mechanical properties. In parallel, a numerical study was developed for structural evaluation. It was observed that the pressurization of the distribution chamber strongly influences the stress of prototype channels. The high-stress region does not surpass the material yield strength for the test pressure. Furthermore, any deformation on the experimental prototype was not observed, indicating that the geometric characteristics guarantee a structural integer of the heat exchanger core. It is highlighted that the numerical results proved a good adherence to experimental results.
【参考中译】 紧凑型换热器因其具有灵活性、几何构型、换热面积比低等特点，在工业中得到了广泛的应用。通常，这些热交换器暴露在较高的温度和压力梯度下，这可能会导致运行过程中的结构故障。在这种情况下，评估了一种采用添加制造的新制造方法来生产该设备。在两台机器上制作了12个模拟换热器几何形状的316L不锈钢样品。搭建了水压试验试验台，通过应变片对其结构完整性进行评价。一些样品被提交到高达700巴的压力下，没有任何泄漏。结果表明，印刷方向对工艺至关重要，影响材料性能，从而观察到von Mise应力。垂直方向上的特性表现出较低的应力水平。热处理的影响也得到了验证，表明加工过程局部地改变了机械性能。同时，还开展了结构评估的数值研究。观察到，配电室的加压对原型通道的应力有很大影响。高应力区不超过测试压力下的材料屈服强度。此外，实验样机没有观察到任何变形，表明换热器的几何特性保证了换热器核心的结构完整性。结果表明，数值结果与实验结果吻合较好。
【来源】 International Journal of Pressure Vessels and Piping 2022, vol.199