To an aircraft, the accuracy of aerodynamic configuration has a direct influence on flight performance. To improve the assembly accuracy of aircraft wing components, two kinds of positioning method and the corresponding assembly precision are studied, and a low-cost flexible assembly tooling system for different wing components is proposed. First, the article analyzes the technological characteristics of airplane wing skin and determines the assembly requirement. Second, positioning method based on contour boards and coordination holes and their assembly precision are researched. Third, to verify the positioning method and the algorithm of assembly precision calculation based on coordination holes, a locating unit with three motion axes is designed and manufactured. Fourth, experimental verification is done and the corresponding results are analyzed. Experiment results showed the assembly precision based on coordination holes has an improvement of 24% contrasting with the precision based on contour boards, and the assembly productivity is increased by 60%. The flexible assembly tooling system also has a demonstration effect for other flexible assembly tooling within the aerospace industry.
feiyan guo Yong-gang Kang , (2016),"Modeling and predicting of aeronautical thin-walled sheet metal parts riveting deformation", Assembly Automation, Vol. 36 Iss 3 pp. -Permanent link to this document: http://dx.If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation.Modeling and predicting of aeronautical thin-walled sheet metal parts riveting deformation Abstract Purpose -Riveting deformation is inevitable due to local relatively large material flows and typical compliant parts assembly, which affects the final product dimensional quality and fatigue durability. However, traditional approaches are concentrated on elastic assembly variation simulation and do not consider the impact of local plastic deformation. This paper presents a successive calculation model to study the riveting deformation where local deformation is taken into consideration. Design/methodology/approach -Based on the material constitutive model and friction coefficient obtained by experiments, an accurate three-dimension finite element (FE) model was built primarily using ABAQUS and verified by experiments. A successive calculation model of predicting riveting deformation was implemented by the Python and Matlab and solved by the ABAQUS. Finally, three configuration experiments were conducted to evaluate the effectiveness of the model. Findings -The model predicting results, obtained from both two simple coupons and a wing panel, showed that the model it was a good compliant with the experimental results and the riveting sequences had a significant effect on the distribution and magnitude of deformation. Practical implications -The proposed model to predict of predicting the deformation from riveting process was available in the early design stages and some efficient suggestions for controlling deformation could be obtained. Originality/value -A new predicting model of thin-walled sheet metal parts riveting deformation was presented to help the engineers to predict and control the assembly deformation more exactly.
Foams are widely used in protective applications requiring high energy absorption under impact, and evaluating impact properties of foams is vital. Therefore, a novel test method based on a shock tube was developed to investigate the impact properties of closed-cell polyethylene (PE) foams at strain rates over 6000 s−1, and the test theory is presented. Based on the test method, the failure progress and final failure modes of PE foams are discussed. Moreover, energy absorption capabilities of PE foams were assessed under both quasi-static and high strain rate loading conditions. The results showed that the foam exhibited a nonuniform deformation along the specimen length under high strain rates. The energy absorption rate of PE foam increased with the increasing of strain rates. The specimen energy absorption varied linearly in the early stage and then increased rapidly, corresponding to a uniform compression process. However, in the shock wave deformation process, the energy absorption capacity of the foam maintained a good stability and exhibited the best energy absorption state when the speed was higher than 26 m/s. This stable energy absorption state disappeared until the speed was lower than 1.3 m/s. The loading speed exhibited an obvious influence on energy density.
Riveting parameters have significant effects on the material growth/material expansion and quality of a joint. However, the inhomogeneity of material growth leads to assembly deformation and degrades the dimensional accuracy of the final products. This study aims to propose an integration method to optimize riveting parameters using finite element method and Kriging metamodels with particle swarm optimization in slug rivet joint. Five key process parameters were considered in this article, including squeezing force, buck cavity, upsetting rise time, upsetting dwell time, and clamping force between sheets. First, a quarter three-dimensional finite element model was established to acquire the simulation results of rivet hole expansion and sheet bulging value. Based on the finite element method results, Kriging surrogate models were built to reflect the mapping relationship between process parameters and the focused target. Subsequently, a multi-objective optimization method, particle swarm optimization, was used to search for Pareto-optimal solution. Finally, by comparing the assembly deformation with 10-rivet coupons, the results showed that the optimized riveting parameters could improve the deformation homogeneity.
Slug rivet is widely used in aircraft assembly due to the higher interference fit level and the longer fatigue life. However, the inhomogeneity of riveting interference value along the thickness direction of the aircraft panels always leads to inevitable deformation, which significantly degrades the dimensional accuracy of the final products. In this study, a quantitative model is established to describe the relationship between several riveting parameters (i.e. squeezing force, buck cavity, upsetting rise time, upsetting dwell time and clamping force between sheets) and the deformation of a formed slug rivet joint. Then the coefficient of variance (CV) is introduced to evaluate the homogeneity of deformation. Subsequently, an optimized combination of the presented parameters is obtained by using finite element method (FEM) simulation so as to generate more uniform deformation. Finally, the FEM model is validated by a series of orthogonal experiments conducted in G86 fully automated C-frame riveting machine and the results show that the squeezing force and the buck cavity are the main significant factors and contributors to the riveted joints deformation, and the sequence of this effect from the high to low are: upsetting dwell time, clamping force, and upsetting rise time. The results also indicate that the developed FE model can be used for further analysis, including the prediction of large component riveting deformation and the mechanical properties of riveted joint.
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