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ICICLE: A Model for Glaciated & Mixed Phase Icing for Application to Aircraft Engines

Rolls-Royce Plc-Geoffrey Jones, Benjamin Collier
University of Oxford-Alexander Bucknell, Matthew McGilvray, David Gillespie, Xin Yang
Published 2019-06-10 by SAE International in United States
High altitude ice crystals can pose a threat to aircraft engine compression and combustion systems. Cases of engine damage, surge and rollback have been recorded in recent years, believed due to ice crystals partially melting and accreting on static surfaces (stators, endwalls and ducting). The increased awareness and understanding of this phenomenon has resulted in the extension of icing certification requirements to include glaciated and mixed phase conditions. Developing semi-empirical models is a cost effective way of enabling certification, and providing simple design rules for next generation engines. A comprehensive ice crystal icing model is presented in this paper, the Ice Crystal Icing ComputationaL Environment (ICICLE). It is modular in design, comprising a baseline code consisting of an axisymmetric or 2D planar flowfield solution, Lagrangian particle tracking, air-particle heat transfer and phase change, and surface interactions (bouncing, fragmentation, sticking). In addition, an efficient particle tracking method has been developed into the code, which employs the representative particle size distribution at each injection location and a deterministic particle sticking method by using an in-situ particle based…
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A Feature-Based Responses Prediction Method for Simplified CAE Models

China Automotive Engineering Research Institute Co., Ltd.-Qingjiang Zhao, Wei Xu
Chongqing University-Huijie Xu, Xin Yang, Wenxiang Dong
Published 2019-04-02 by SAE International in United States
In real-world engineering problems, the method of model simplification is usually adopted to increase the simulation efficiency. Nevertheless, the obtained simulation results are commonly with low accuracy. To research the impact from model simplification on simulation results, a feature-based predictive method for simplified CAE model analysis is proposed in this paper. First, the point clouds are used to represent the features of simplified model. Then the features are quantified according to the factors of position for further analysis. A formulated predictive model is then established to evaluate the responses of interest for different models, which are specified by the employed simplification methods. The proposed method is demonstrated through an engineering case. The results suggest that the predictive model can facilitate the analysis procedure to reduce the cost in CAE analysis.
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An Integrated Deformed Surfaces Comparison Based Validation Framework for Simplified Vehicular CAE Models

Chongqing University-Xin Yang, Zhenfei Zhan, Qingmiao Wang, Ping Wang, Yudong Fang, Ling Zheng
Published 2018-04-03 by SAE International in United States
Significant progress in modeling techniques has greatly enhanced the application of computer simulations in vehicle safety. However, the fine-meshed impact models are usually complex and take lots of computational resources and time to conduct design optimization. Hence, to develop effective methods to simplify the impact models without losing necessary accuracy is of significant meaning in vehicle crashworthiness analysis. Surface deformation is frequently regarded as a critical factor to be measured for validating the accuracy of CAE models. This paper proposes an integrated validation framework to evaluate the inconsistencies between the deformed surfaces of the original model and simplified model. The geometric features and curvature information of the deformed surfaces are firstly obtained from crash simulation. Then, the magnitude and shape discrepancy information are integrated into the validation framework as the surface comparison objects. Finally, the proposed method is implemented on a crash case to verify its efficiency and feasibility in vehicle safety simulations.
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Design Optimization of Vehicle Body NVH Performance Based on Dynamic Response Analysis

Chongqing University-Jun Lu, Zhenfei Zhan, Haozhan Song, Xu Liu, Xin Yang, Junqi Yang
Published 2017-03-28 by SAE International in United States
Noise-vibration-harshness (NVH) design optimization problems have become major concerns in the vehicle product development process. The Body-in-White (BIW) plays an important role in determining the dynamic characteristics of vehicle system during the concept design phase. Finite Element (FE) models are commonly used for vehicle design. However, even though the speed of computers has been increased a lot, the simulation of FE models is still too time-consuming due to the increase in model complexity. For complex systems, like vehicle body structures, the numerous design variables and constraints make the FE simulations based optimization design inefficient. This calls for the development of a systematic and efficient approach that can effectively perform optimization to further improve the NVH performance, while satisfying the stringent design constraints.In the present work, an efficient method to optimize the structural dynamic response is proposed considering the low-frequency NVH performances. As a first step, to reduce computational burden, a response sensitivity analysis is performed to detect the most important variables prior to the design optimization. Then an analytical approximation model of vibration resonance peak…
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A Similarity Evaluation Metric for Mesh Based CAE Model Simplification and Its Application on Vehicle

Chongqing University-Xin Yang, Zhenfei Zhan, Nanliang Jiang, Junqi Yang, Jun Lu
Published 2017-03-28 by SAE International in United States
To obtain higher efficiency in analysis process, simplification methods for computer-aided engineering (CAE) models are required in engineering. Current model simplification methods can meet certain precision and efficiency requirement, but these methods mainly concentrate on model features while ignoring model mesh which is also critical to efficiency of the analysis process and preciseness of the results. To address such issues, an integrated mesh simplification and evaluation process is proposed in this paper. The mesh is simplified to fewer features (e.g. faces, edges, and vertices) through edge collapsing based on quadric error metric. Then curvatures and normal vectors which are the objects to be evaluated are extracted from the original and simplified models for comparison. To obtain accurate results, the geometric information of mesh nodes and elements are both considered in this evaluation process. The proposed method is implemented on a vehicle crash test. The results demonstrate the feasibility of the proposed integrated method.
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An Engineering Approach to Predict Fracture and Tearing

GM Technical Center India Ltd. - General Motors Company-Varun Rao
General Motors Company-Kangping Wang, Yih-Charng Deng, Xin Yang
Published 2011-04-12 by SAE International in United States
An engineering approach was developed to extract the failure plastic strain, thinning failure strain, and major in plane failure strain for finite element simulation applications. This approach takes into account the failure strain dependency on the element size when element deletion scheme is invoked in the simulation of material fracture. Both localized necking fracture and tensile shear fracture can be predicted when appropriate elements and material models are used in LS-DYNA simulations. This leads to a more accurate prediction of fracture and tearing in the finite element simulation of vehicle structure and crash loading conditions.
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Effect of Stress Softening in Bumper Foams on the Low Speed Impact Performance of Vehicles

SAE International Journal of Materials and Manufacturing

State Key Laboratory of Automotive Safety and Energy, Tsinghua University-Yong Xia, Xin Yang, Qing Zhou
  • Journal Article
  • 2008-01-1126
Published 2008-04-14 by SAE International in United States
The experimental findings have revealed that there is a significant stress softening phenomenon for the polymer foams used in vehicle bumpers after they are loaded repeatedly from the raw undeformed state. With a series of loading-unloading test data under different maximum strains, dependence of the stress softening on the deformation history is analyzed. The corresponding material models in ABAQUS are chosen to characterize such special features of the polymer foams in FEA. The low speed impact models of a subsystem consisting of a bumper assembly and front-rails are established, and a process for transferring the deformation history of the bumper foams between the consecutive impact-loading cases is set up in the environment of ABAQUS. Based on the FE simulations, it can be seen that the stress softening of the polymer foams compromises the low speed impact performance of bumpers in subsequent impacts. Therefore the stress softening effect of polymer foams should be taken into account during safety designs of vehicle bumpers.
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