Method for in-situ measurement of near-consolidation zone temperature profiles for laser-based Automated Fiber Placement (InSiTe)

基于激光的自动纤维铺放（AFP）能够使用热塑性基体材料原位生产纤维复合材料结构，从而消除了对能源密集型高压釜工艺的需求。此外，改进的可回收性以及互锁连接技术带来了进一步的优点。挑战在于实现与高压灭菌工艺相当的机械性能。通过热机械过程控制来设定接合强度，该过程控制理想地基于接合区域中的热机械条件的知识。然后可以使用已知的模型来预测层间强度，从而可以最大限度地减少耗时和成本密集的测试方法，并且如果需要，可以在过程中提高质量。这里的一个问题是接合区中的温度历史的过程中测量。虽然接合区之前和之后的温度可以通过红外热成像法记录，但实际接合区被固结辊覆盖。插入层压板中的热电偶或光纤传感器仅选择性地测量温度，并专门用于模型验证，尽管它们也作为干扰点，因此高估或低估了温度。因此，目前不存在获得关于连续AFP工艺中的接合区内的温度历史的经验知识的方法。为此，我们在前期工作中设计了一种新的测量方法，即在固结辊上安装光纤瑞利传感器。因此，本项目的目的是探索嵌入在AFP典型的形状自适应固结辊中的瑞利传感器的热机械灵敏度，从而实现基于激光的AFP温度传感测量方法。为此，将进行纤维嵌入和由此产生的热和机械灵敏度的实验研究。研究结果将用于补偿机械和热干扰，使剩余的应变是热应变。在进一步的研究中，将开发一种基于模型的方法来校准敏感的固结辊，通过相关的热应变与温度曲线。将干扰补偿与基于模型的校准相结合将使得能够在基于连续辊的制造过程（诸如基于激光的AFP）中进行温度检测。

Laser-based Automated Fiber Placement (AFP) enables the in-situ production of fiber composite structures using thermoplastic matrix materials, thus eliminating the need for an energy-intensive autoclave process. In addition, further advantages arise from improved recyclability as well as interlocking joining techniques. The challenge is to achieve mechanical properties equivalent to the autoclave process. The joint strength is set by thermal-mechanical process control, which is ideally based on knowledge of the thermal-mechanical conditions in the joining zone. Known models can then be used to predict the interlaminar strengths, so that time-consuming and cost-intensive test methods can be minimized and, if necessary, quality can be improved during the process. One problem here is the in-process measurement of the temperature history in the joining zone. While the temperature before and after the joining zone can be recorded by IR thermography, for example, the actual joining zone is covered by the consolidation roller. Thermocouples or fiber optic sensors inserted into the laminate measure the temperature only selectively and are used exclusively for model validation, although they also act as interference points and therefore overestimate or underestimate the temperature. Accordingly, no method currently exists to obtain empirical knowledge about the temperature history within the joining zone in the continuous AFP process. For this reason, a new measuring method was designed in our own preliminary work, in which the consolidation roller is equipped with fiber-optic Rayleigh sensors. This creates a strain-sensitive shell surface that is in continuous contact with the joining zone and thus enables the detection of thermal-mechanical conditions.Therefore, the aim of this project is to explore the thermal-mechanical sensitivity of Rayleigh sensors embedded in a shape-adaptive consolidation roller typical for AFP, thus enabling the measurement method for temperature sensing in laser-based AFP. To this end, experimental studies of fiber embedding and the resulting thermal and mechanical sensitivities will be conducted. The findings will be used to compensate for mechanical as well as thermal disturbances so that the remaining strains are thermal strains. In further investigations, a model-based method for calibrating the sensitive consolidation roll will be developed by correlating the thermal strains with the temperature curves. Combining the disturbance compensation with the model-based calibration will enable temperature detection in a continuous roller-based manufacturing process, such as laser-based AFP.