Residual Stressesin intrinsic hybrid laminates, detection, modification and consideration in manufacturing and the numeric damage modeling

本质混合层压板中的残余应力、制造中的检测、修改和考虑以及数值损伤建模

• 批准号: 256131096
• 负责人: Professor Dr.-Ing. Michael Sinapius
• 金额: --
• 依托单位: Institut für Mechanik und Adaptronik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/256131096?language=en
• 关键词: Residual; Stressesin; intrinsic; hybrid; laminates

The different thermal properties of the components as well as the anisotropy of hybrid CFRP-metal-composites lead to intrinsic high residual stresses during the production processes reducing in turn the strength of the hybrid composite. The project aims to investigate measures to reduce the interlaminar stresses. Therefore, measurement technologies are investigated for measuring the existing or nascent residual stresses. The focus lies on the application of fiber optical sensors being directly integrated into the uncured fibre reinforced polymer. Measures for modifying the level of residual stresses are investigated subsequently. Parametric mass screenings reveal the cause-effect relationships between the material parameters and the process parameters as well as the interlaminar residual stresses.Beside the intrinsic stresses asymmetric layups lead to process-induced deformations like curvatures or deflections. Curved structures exhibit significant complex stress states.The developed measurement principle will be adapted such that beside the determination of the residual stresses statements about the sources of process-induced deformation can be made. The achieved perceptions from the first funding period about the origin of residual stresses, the influence of different intrinsic and extrinsic factors are used to discover the cause-effect relationships between the process-induced deformation evoked by the structural curvature, the asymmetry, and the embedded residual stresses. Beside measures for reducing these stresses compensating methods for producing dimensionally accurate structures are investigated for hybrid structures. The developed compensating methods are used to manufacture accurate flat asymmetric coupons for CAI investigations. The effect on the damage behavior will be investigated experimentally.

部件的不同热性能以及混合 CFRP-金属复合材料的各向异性导致生产过程中固有的高残余应力，从而降低了混合复合材料的强度。该项目旨在研究减少层间应力的措施。因此，研究了用于测量现有或新生残余应力的测量技术。重点在于将光纤传感器直接集成到未固化的纤维增强聚合物中的应用。随后研究了改变残余应力水平的措施。参数质量筛选揭示了材料参数和工艺参数以及层间残余应力之间的因果关系。除了固有应力之外，不对称叠层还会导致工艺引起的变形，例如曲率或偏转。弯曲结构表现出显着的复杂应力状态。所开发的测量原理将进行调整，以便除了确定残余应力之外，还可以做出有关过程引起的变形来源的陈述。从第一个资助阶段获得的关于残余应力起源、不同内在和外在因素的影响的认识被用来发现结构曲率、不对称性和嵌入残余应力引起的过程引起的变形之间的因果关系。除了减少这些应力的措施之外，还研究了混合结构生产尺寸精确的结构的补偿方法。所开发的补偿方法用于制造用于 CAI 研究的精确平面不对称优惠券。将通过实验研究对损伤行为的影响。