Heat Assisted Local Forming and Joining Processes: Simulation and Experimentation

热辅助局部成型和连接工艺：模拟和实验

• 批准号: RGPIN-2019-05972
• 负责人: Champliaud, Henri
• 金额: $ 2.84万
• 依托单位: École de technologie supérieure
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=738631
• 关键词: Heat; Assisted; Local; Forming; Joining

The increasing demand in the automotive and aerospace industries for higher properties in their manufactured parts is closely connected to the lower thickness of the sheet metal that could be involved in the forming processes and consequently the lighter weights of these parts at the end. The main concern is the poor formability of high grade materials, especially at room temperature. For this reason, many efforts are actually made towards warm to high temperature sheet metal manufacturing processes but there is still an important gap between the prediction of the numerical models and the actual processes because of the complex evolution of the microstructure during forming at elevated temperature. One aspect following a heat assisted forming process is the transformation induced plasticity effect (TRIP) in the microstructure that can occur in phase changing materials. Higher hardening capability are exhibited following this transformation and one can take an advantage of the enhanced properties of the manufactured parts to decrease furthermore their thicknesses for weight reduction and then improved fuel efficiency in transportation. A typical example of a dynamic heat assisted forming process involving hard-to-shape high strength materials is the sheet-metal spinning for aerospace applications. The process progressively transform flat metal blank into hollow shapes, mainly with axisymmetric profiles. The method uses a tool i.e. a roller which forces a metal blank onto a revolving mandrel. The roller is pressed against the blank and is moved axially into complex trajectories to achieve finally a hollow-shaped product. With the great number of parameters (speed, temperature dependent properties, strain rate, tool trajectories, induced anisotropy.) involved in the procedure a comprehensive design of experiments would be too demanding in terms of costs and dedicated time. Finite element models are of great help to reproduce complex processes and can offer very in deep details on the ongoing forming process and the final properties of the parts. The key is the accurate information input in the numerical model and its ability to reproduce precisely the heat transfer, the strain hardening, the anisotropy and eventually the TRIP phenomena. In this project, the focus will be on the simulation model and its ability to represent these phenomena evolving with time in the material. A crystal plasticity model will be implemented in the finite element analysis to follow these complex evolutions. Eventually, phase transformation could be monitored with the appropriate amount of locally heat input at the forming tool contact zone to enhance the sheet metal formability. The goal is to bring conventional forming processes to new technological levels by adding high tech heating sources (like laser heating) in the forming steps of hard to shape high strength materials, enhancing material properties and maintaining heat assisted operation at lowest cost as possible.

汽车和航空航天行业对其制造零件的更高性能的需求日益增加，这与成形过程中可能涉及的板材厚度较低以及最终这些零件的重量较轻密切相关。主要的担忧是高级材料的成形性较差，特别是在室温下。为此，人们对板料的温变高温成形工艺进行了大量的研究，但由于高温成形过程中微观组织的复杂演变，使得数值模型的预测与实际成形过程之间仍存在较大差距。热辅助成形过程的一个方面是相变材料微观结构中可能出现的相变诱导塑性效应(TRIP)。这种转变后表现出更高的硬化能力，人们可以利用制造部件的增强性能来进一步减少它们的厚度，从而减轻重量，从而提高运输中的燃料效率。航空航天用板材旋压是涉及难以成形的高强度材料的动态热辅助成形工艺的一个典型例子。该过程逐渐将扁平金属坯料转变为中空形状，主要是轴对称型材。该方法使用一种工具，即滚子，其将金属坯料强制到旋转心轴上。轧辊被压在坯料上，并沿轴向移动到复杂的轨迹中，最终得到中空形状的产品。具有大量的参数(速度、与温度相关的特性、应变率、刀具轨迹、诱导各向异性)。参与这一程序的综合实验设计在成本和专门时间方面要求太高。有限元模型非常有助于再现复杂的过程，可以提供正在进行的成形过程和零件的最终性能的非常详细的信息。关键是在数值模型中输入准确的信息，以及它能够精确地再现热传递、应变硬化、各向异性以及最终的跳闸现象。在这个项目中，重点将放在模拟模型及其在材料中表示这些随时间演变的现象的能力上。在有限元分析中将采用晶体塑性模型来跟踪这些复杂的演化过程。最终，可以通过在成形工具接触区输入适量的局部热来监控相变，以提高板材的成形性。其目标是通过在难以成形的高强度材料的成形步骤中增加高科技热源(如激光加热)，将传统成形工艺提高到新的技术水平，提高材料的性能，并以尽可能低的成本保持热辅助操作。