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

部件的不同热性能以及混杂CFRP-金属-复合材料的各向异性导致在生产过程期间固有的高残余应力，从而降低混杂复合材料的强度。该项目旨在研究降低层间应力的措施。因此，测量技术的研究，用于测量现有的或新生的残余应力。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。随后研究了修改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，除了内应力外，非对称铺层还会导致弯曲或挠度等工艺诱导变形。弯曲结构具有显著的复杂应力状态。开发的测量原理将适用于除了确定残余应力外，还可以对过程引起的变形源进行说明。从第一个融资期的残余应力的起源，不同的内在和外在因素的影响所取得的看法被用来发现的过程引起的变形引起的结构曲率，不对称性，和嵌入的残余应力之间的因果关系。此外，还研究了混合结构的应力补偿方法。开发的补偿方法用于制造精确的平面非对称试样的CAI调查。对损伤行为的影响将进行实验研究。

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.