Strain Path Control and Defect Formation and Suppression During Forming of Highly Contoured Composite Parts Using Active Tooling

航空航天工业的特点是需要大量高性能部件的复杂产品，但这种产品的复杂性与极低的批量吞吐量形成鲜明对比。对于航空航天应用，先进的复合材料提供了许多优于金属的优势，包括相对较高的比强度和弹性模量，这可以导致定制形状和微观结构，以满足性能要求。不幸的是，在这个行业中，复合材料部件的使用受到了先进复合材料部件的制造成本和时间的严重限制，同时需要以高昂的费用存储和维护许多未充分利用的模具。为了满足这一需求，目前正在考虑使用主动离散工具（即，在成形过程中根据电子存储的几何形状改变形状的引脚矩阵工具）进行复合材料成形。最近，pi已经成功地证明了：(1)使用主动工具进行复合材料成形是可能的；(2)它增加了通过成形过程可以成功制造的部件数量。此外，由于使用了单一的可重构工具，因此大大简化了模具开发和存储。这个由美国国家科学基金会资助的为期3年的项目将寻求对复合材料主动成形过程的基本理解，特别强调工艺变量对零件成形性和纤维重定向的影响。研究将集中在工艺开发和开发数学模型和数值建模方案，这些方案将材料变形模式与形成复杂形状所必需的先进成形技术和几何特征联系起来。该项目包括诺斯罗普·格鲁曼公司以材料测试、复合材料成型专业知识和更大的可重构工具的形式提供支持，从而更快地将技术转移到航空航天工业。此外，该提案还包括本科生（REU）的参与，并将研究整合到具体的本科和研究生课程中，作为案例研究、学期设计项目和实验室练习。总的来说，所提出的研究有可能显著提高零件的可成形性，并减少由复合材料板制成的相对较大的零件的中低体积成形的工艺时间和成本。这可以从航空航天扩展到专门的汽车、船舶和生物医学应用。该研究还将改进复合材料成形模拟，这是目前扩大复合材料使用的主要障碍。

Complex products requiring a large number of high-performance parts characterize the aerospace industry, but this product complexity is contrasted by an extremely low volume throughput. For aerospace applications, advanced composite materials offer a number of advantages over metals including relatively high specific strengths and elastic moduli, which can lead to tailoring of shape and microstructure to meet performance requirements. Unfortunately, the use of composite parts in this industry has been severely limited by the prohibitive fabrication cost and time of advanced composite component, along with the need to store and maintain many under-utilized molds at great expense. In response to this need, the use of active discrete tooling (i.e., matrix of pins tooling that changes shape during the forming process based on electronically stored geometry) for composites forming is currently being considered. Recently, the PIs have successfully demonstrated that (1) composite forming using active tooling is possible and (2) it increases the number of components that can be successfully manufactured by the forming process. In addition, mold development and storage is greatly simplified because a single reconfigurable tool is used. This 3-year project sponsored by the National Science Foundation will seek to develop a fundamental understanding of composites forming process with active tooling, emphasizing particularly the effects of process variables on part formability and fiber reorientation. The research will concentrate on process development and on developing mathematical models and numerical modeling schemes that relate the material deformation modes necessary to form complex shapes, to advanced forming techniques and geometric features. The project includes support from Northrop Grumman in the form of materials testing, expertise in composites forming, and access to a larger reconfigurable tool, resulting in more rapid technology transfer to the aerospace industry. In addition, the proposal includes involvement of undergraduates (REU) and the integration of the research into specific undergraduate and graduate courses as case studies, semester design projects, and laboratory exercises. Overall, the proposed research has the potential to significantly improve part formability and reduce process time and cost for low to medium volume forming of relatively large parts from composite sheet. This can extend beyond aerospace to specialized automotive, marine, and biomedical applications. The research will also lead to improved simulation of composites forming, which is currently a major barrier to expanded use of composites.