Browsing by Author "An, Luling"

Now showing 1 - 4 of 4
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    Dynamic analysis on single-rotor multi-input helicopter main gearbox related with structural parameters
    (Sage, 2019-09-26) Zhang, Wei; An, Luling
    Combined with the finite element method and the lumped mass method, the integral node dynamic model of a single-rotor multi-input helicopter main gearbox is established. The influence of shaft parameters on dynamic characteristics is analyzed, and each torsional shaft is regarded as a finite element node to derive the system dynamic equation. In addition, the dynamic model of the meshing pair element is established by lumped mass method, and these elements not only include internal excitations such as time-varying meshing stiffness and transmission error, but also carry the external load. The differential equations of the system are solved by the Fourier series method. The dynamic responses of the converging element and the planetary gear train are obtained. The load-sharing coefficients of these elements are calculated by the influence of the shaft structural parameters. A parameter optimization method is proposed to improve the system load characteristics, which provides a theoretical support for the design of helicopter main transmission system
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    Optimisation for clamping force of aircraft composite structure assembly considering form defects and part deformations
    (Hindawi Publishing Corporation / SAGE, 2021-04-15) Zhang, Wei; An, Luling; Chen, Yuan; Xiong, Yeping; Liao, Yabing
    Given the existence of manufacturing defects and the accumulation of assembly errors, non-compliant assembly appears between components, especially for composite structure assembly. In the engineering application, the clamping force (CF) is often used to eliminate the clearance between mating components, but the improper CF may result in unwanted structure failure. Thus, on the premise of ensuring the safety of composite parts, this study proposes a procedure to systematically optimise the assembly CF. Firstly, the components mating surfaces were obtained by laser scanner, and the matching of actual surfaces was transformed and simplified based on ‘equivalent surface’ concept. Then, a mathematical optimisation model was established. The CF layout and magnitude were taken as variables, and the clearance elimination rate and the overall assembly force value were employed as objective functions. Finally, the improved genetic algorithm (GA) was used to solve this problem. A parametric finite element analysis (FEA) model was built, and model accuracy was verified by physical experiments. The finite element calculation and post-processing were carried out by Python script in ABAQUS®. Compared to the engineer’s traditional approach, the influence of form defects and part deformations were considered, which can help control the assembly stress well and ensure product performance.
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    Posture optimization algorithm for large structure assemblies based on skin model
    (Hindawi, 2018-10-18) Zhang, Wei; An, Luling; Sherar, Peter; Tian, Wei
    Geometric deviations inevitably occur in product manufacturing and seriously affect the assembly quality and product functionality. Assembly simulations on the basis of computer-aided design (CAD) package could imitate the assembly process and thus find out the design deficiencies and detect the assemblability of the components. Although lots of researches have been done on the prediction of assembly variation considering the geometric errors, most of them only simplify the geometric variation as orientation and position deviation rather than the manufacturing deformation. However, in machinery manufacturing, even if the manufacturing defects are limited, they could propagate and accumulate through components and lead to a noncompliant assembly. Recently, many point-based models have been applied to assembly simulation; however they are mainly interested in simulating the resulting positions of the assembled parts and lack the consideration of the postprocessing after positioning. This paper enriches the complete assembly simulation process based on skin model and presents a simple and effective posture evaluation and optimization method. The studied approach includes a software algorithm applied to evaluate the contact state of the assembly parts and a mathematical model based on the particle swarm optimization to acquire the optimal assembly posture. To verify the efficiency and feasibility of the proposed method, a case study on the aircraft wing box scaling model assembly is performed.
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    Progressive damage numerical modelling and simulation of aircraft composite bolted joints bearing response
    (MDPI, 2020-12-08) Gao, Guoqiang; An, Luling; Giannopoulos, Ioannis K.; Han, Ning; Ge, Ende; Hu, Geng
    Finite element numerical progressive damage modelling and simulations applied to the strength prediction of airframe bolted joints on composite laminates can lead to shorter and more efficient product cycles in terms of design, analysis and certification, while benefiting the economic manufacturing of composite structures. In the study herein, experimental bolted joint bearing tests were carried out to study the strength and failure modes of fastened composite plates under static tensile loads. The experimental results were subsequently benchmarked against various progressive damage numerical modelling simulations where the effects of different failure criteria, damage variables and subroutines were considered. Evidence was produced that indicated that both the accuracy of the simulation results and the speed of calculation were affected by the choice of user input and numerical scheme.