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In this paper, a theoretical model of the contact characteristics for layers on irregular surfaces is established by analyzing the contact deformation and slip ratio at the placement path points. Based on this model, a numerical algorithm for calculating the contact characteristics at any path point is proposed. The normal stress field, tangential stress field, and contact status of the contact area at four path points on the double-curved surface mold are obtained using the algorithm and verified through experiments. The results indicate that the model can be used to predict the contact characteristics at any placement path point, and the possible defects at points P3 and P4 are initially identified by analyzing the contact characteristics. In addition, compared to the 8-h computational time required for simulation calculation, this numerical algorithm takes only 20 ms to compute, which shows that the developed model has greatly reduced the calculation time. [ABSTRACT FROM AUTHOR]

Aircraft panel automatic drilling and riveting system is the key equipment to realize aircraft panel assembly with high efficiency and quality. In practical application, automatic drilling and riveting system should bear cyclic riveting force with large load, which means such systems must have enough stiffness to deal with this situation. The stiffness of each components in automatic drilling and riveting system reflects as the end stiffness finally; in the meanwhile, end stiffness and riveting ability of the system will be affected when the posture of the system changes. According to this situation, stiffness matrixes related to mechanics characteristic of motion axes, transmission parts, inner-side working head, and outer-side working head of automatic horizontal dual-machine cooperative drilling and riveting system are established, in which the Jacobi matrix method, point transformation matrix method, and finite element analysis are applied. Finally, the static end stiffness model is proposed based on multi-body small deflection theory. The end stiffness model has been validated through experimental measurement, and the stiffness relationship of dual-machine tool system was obtained, which applied important data for structure optimization and control system design. [ABSTRACT FROM AUTHOR]