scholarly journals Effect of Riveting Angle and Direction on Fatigue Performance of Riveted Lap Joints

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 236
Author(s):  
Qingxiao Liang ◽  
Tianpeng Zhang ◽  
Chunrun Zhu ◽  
Yunbo Bi

Riveting is the most commonly used connection method in aircraft assembly, and its quality has a crucial effect on the fatigue performance of aircraft. Many factors affect the riveting quality, among which the influence of the riveting angle and direction is not clear. In this paper, a three-dimensional finite element model of single-rivet lap joints is established and verified by the driven head geometry and the riveting force data obtained from the riveting experiments. Then, by adjusting the angle and direction of the punch in the finite element model, the riveting process is simulated at the angles of 0°, 1°, 2°, and 3° and the directions of 0° and 180° to investigate the deformation of the lap joints, the stress distribution around the hole, and the stress distribution of the rivet. Finally, the fatigue tests of the single-rivet lap joints are performed and the influence of the riveting angle and direction on the connection quality and fatigue performance of the riveting joints is analyzed.

2009 ◽  
Vol 131 (12) ◽  
Author(s):  
Feng Xie ◽  
Liu Yang ◽  
Lin Guo ◽  
Zhi-jun Wang ◽  
Gang Dai

To establish a finite element model that reflects the geometric characteristics of the normal anterior cruciate ligament (ACL), explore the approaches to model knee joint ligaments and analyze the mechanics of the model. A healthy knee joint specimen was subjected to three-dimensional laser scanning, and then a three-dimensional finite element model for the normal ACL was established using three-dimensional finite element software. Based on the model, the loads of the ACL were simulated to analyze the stress-strain relationship and stress distribution of the ACL. Using the ABAQUS software, a three-dimensional finite element model was established. The whole model contained 22,125 nodes and 46,411 units. In terms of geometric similarity and mesh precision, this model was superior to previous finite element models for the ACL. Through the introduction of material properties, boundary conditions, and loads, finite elements were analyzed and computed successfully. The relationship between overall nodal forces and the displacement of the ACL under anterior loads of the tibia was determined. In addition, the nephogram of the ACL stress spatial distribution was obtained. A vivid, three-dimensional model of the knee joint was established rapidly by using reverse engineering technology and laser scanning. The three-dimensional finite element method can be used for the ACL biomechanics research. The method accurately simulated the ACL stress distribution with the tibia under anterior loads, and the computational results were of clinical significance.


Author(s):  
O. E. C. Prizeman ◽  
V. Sarhosis ◽  
A. M. D’Alri ◽  
C. J. Whitman ◽  
G. Muratore

Caerphilly Castle (1268-70) is the first concentric castle in Britain and the second largest in the UK. The dramatic inclination of its ruinous south west tower has been noted since 1539. Comparing data from historical surveys and a terrestrial laser scan undertaken in 2015, this paper seeks to review evidence for the long-term stability of the tower. Digital documentation and archival research by architects is collated to provide data for structural analysis by engineers. A terrestrial laser scan was used to create a detailed three dimensional finite element model to enable structural analysis of the current shape of the tower made by tetrahedral elements. An automated strategy has been implemented for the transformation of the complex three dimensional point cloud into a three dimensional finite element model. Numerical analysis has been carried out aiming at understanding the main structural weaknesses of the tower in its present condition. Comparisons of four sets of data: 1539, 1830, 1870 and 2015 enabled us to determine change albeit between very different methods of measurement.


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