Thin-layer element modeling method of aero-engine bolted joints

2016 ◽  
pp. 477-482
Author(s):  
X Yao ◽  
J Wang ◽  
X Zhai
Keyword(s):  
Thin Layer ◽  
Modeling Method ◽  
Bolted Joints ◽  
Element Modeling ◽  
Aero Engine

Research and application of improved thin-layer element method of aero-engine bolted joints

2016 ◽  
Vol 231 (5) ◽  
pp. 823-839 ◽  
Author(s):  
Xingyu Yao ◽  
Jianjun Wang ◽  
Xue Zhai
Keyword(s):  
Stress Distribution ◽  
Thin Layer ◽  
Contact Stress ◽  
Experimental Results ◽  
Bolted Joints ◽  
Material Parameters ◽  
Aero Engine ◽  
Interface Contact ◽  
Contact Stress Distribution ◽  
Element Method

A new dynamic modeling method called the improved thin-layer element method is proposed to apply to the aero-engine bolted joints. The thin-layer elements are partitioned based on the interface contact stress distribution. In addition, the material parameters of the partitioned thin-layer elements are determined by the bolted joints stiffness technique and the fractal contact theory without the experimental results, which allows the engineer to estimate the dynamic characteristics of whole structure before the physical prototype is available. First, the modeling principles of the improved thin-layer element method are studied and the bolted joints stiffness is analyzed. Next, the material parameters of the partitioned thin-layer elements are determined on the basis of the interface contact stress distribution characteristics of the bolted joints. Finally, this method is applied to the simulative casing bolted joints structure and the results are compared with the experimental results in order to verify the proposed method. The results indicate that the improved thin-layer element method is more accurate than the thin-layer elements method, and the material parameters of the partitioned thin-layer elements can be expressed by the structural parameters of the aero-engine bolted joints without updating based on the experiment.

scholarly journals An Energy-Based Discrete Element Modeling Method Coupled with Time-Series Analysis for Investigating Deformations and Failures of Jointed Rock Slopes

2021 ◽  
Vol 11 (12) ◽  
pp. 5447
Author(s):  
Xiaona Zhang ◽  
Gang Mei ◽  
Ning Xi ◽  
Ziyang Liu ◽  
Ruoshen Lin
Keyword(s):  
Time Series ◽  
Iterative Process ◽  
Discrete Element ◽  
Jointed Rock ◽  
Modeling Method ◽  
Discrete Element Modeling ◽  
Rock Slopes ◽  
Sliding Surface ◽  
Element Modeling ◽  
Displacement Based

The discrete element method (DEM) can be effectively used in investigations of the deformations and failures of jointed rock slopes. However, when to appropriately terminate the DEM iterative process is not clear. Recently, a displacement-based discrete element modeling method for jointed rock slopes was proposed to determine when the DEM iterative process is terminated, and it considers displacements that come from rock blocks located near the potential sliding surface that needs to be determined before the DEM modeling. In this paper, an energy-based discrete element modeling method combined with time-series analysis is proposed to investigate the deformations and failures of jointed rock slopes. The proposed method defines an energy-based criterion to determine when to terminate the DEM iterative process in analyzing the deformations and failures of jointed rock slopes. The novelty of the proposed energy-based method is that, it is more applicable than the displacement-based method because it does not need to determine the position of the potential sliding surface before DEM modeling. The proposed energy-based method is a generalized form of the displacement-based discrete element modeling method, and the proposed method considers not only the displacement of each block but also the weight of each block. Moreover, the computational cost of the proposed method is approximately the same as that of the displacement-based discrete element modeling method. To validate that the proposed energy-based method is effective, the proposed method is used to analyze a simple jointed rock slope; the result is compared to that achieved by using the displacement-based method, and the comparative results are basically consistent. The proposed energy-based method can be commonly used to analyze the deformations and failures of general rock slopes where it is difficult to determine the obvious potential sliding surface.

Finite Element Simulation in the Dynamics Calculation of Bolted-Joint Interface

2012 ◽  
Vol 215-216 ◽  
pp. 1009-1012
Author(s):  
Yan Ting Ai ◽  
Yan Bai ◽  
Xue Zhai ◽  
Dan Zhao
Keyword(s):  
Experimental Data ◽  
Material Properties ◽  
Interface Layer ◽  
Bolted Joints ◽  
Joint Interface ◽  
Bolted Joint ◽  
Linear Dynamic ◽  
Element Simulation ◽  
Aero Engine ◽  
Dynamics Calculation

Many components in modern mechanical structure are connected with bolts, and the behaviour of joints significantly affects the dynamic response of these structures. Based on the software of MSC. patran, firstly, a linear dynamic model for bolted joints and interface is developed. The joint interface is modeled using a technology of interface layer element(ILE) and multi-point constrains(MPC) technique. And then, using the MATLAB language, the properties of ILE material are optimized to simulate the bolted-joint interface stiffness. The material properties parameters are identified by using experimental data. This work takes aero-engine case model as an example, researching its model analysis under different pre-stress conditions to check the method and provide insight on how to model the joint interface in the dynamics calculation of bolted structure.

Nonlinear Effects on the Stiffness of Bolted Joints

1996 ◽  
Vol 118 (1) ◽  
pp. 48-53 ◽  
Author(s):  
T. F. Lehnhoff ◽  
W. E. Wistehuff
Keyword(s):  
Finite Element ◽  
Cast Iron ◽  
Finite Element Modeling ◽  
External Load ◽  
Nonlinear Effects ◽  
Bolted Joints ◽  
Radial Position ◽  
Bolted Joint ◽  
Element Modeling ◽  
Percent Decrease

Axisymmetric finite element modeling of bolted joints was performed to show the effects of the magnitude and position of the external load, member thickness, and member material on the bolt and member stiffnesses. The member stiffness of the bolted joint was found to decrease 10 to 42 percent for the 20-mm to 8-mm bolts, respectively, as the magnitude of the external load was increased. Member stiffness appears to be independent of the radial location of the external load and increases as the member thickness decreases. Member stiffness decreased by a factor of 2.5 to 3 with a change in the member material from steel to aluminum. The cast iron members had a decrease in member stiffness of a factor of 1.7 to 1.9. The aluminum over cast iron combination had a member stiffness between the aluminum and cast iron alone. Bolt stiffnesses varied by less than two percent for changes in the magnitude of the external load for all bolt sizes and member materials, except for the 8-mm bolt where stiffness increased by approximately 11 percent. Changes in radial position of the external load had no effect on the bolt stiffness. A 3 to 13-percent decrease in the bolt stiffness was found when changing from steel to aluminum members. A 2 to 3-percent bolt stiffness decrease resulted when the member material was changed from steel to cast iron and similarly from steel to the aluminum over cast iron combination

Study on Case Library of Parameterized Aero-Engine Overall Structure

2012 ◽  
Vol 215-216 ◽  
pp. 1312-1317
Author(s):  
Jiang Fan ◽  
Jia Rui Zhang ◽  
Rui Zhang ◽  
Xiu Li Shen ◽  
Rong Qiao Wang
Keyword(s):  
Full Advantage ◽  
Object Oriented ◽  
Structure Design ◽  
Modeling Method ◽  
Object Oriented Method ◽  
Top Down ◽  
Case Library ◽  
Similarity Retrieval ◽  
Retrieval Algorithms ◽  
Aero Engine

To take full advantage of and learn from overall structure of existing engine case, this paper presents parameterized, object-oriented method and similarity retrieval algorithms. A case library of parameterized engine overall structure is established by “top-down” master modeling method. On this basis, the management of engine parameters in case library is achieved, which built a foundation for the rapid design of new program at stage of overall structure design.

scholarly journals Nonlinear Modeling and Identification of an Aluminum Honeycomb Panel with Multiple Bolts

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Yongpeng Chu ◽  
Hao Wen ◽  
Ti Chen
Keyword(s):  
Thin Layer ◽  
Plastic Material ◽  
Experimental Tests ◽  
Bolted Joints ◽  
High Excitation ◽  
Material Parameters ◽  
Elastic Plastic ◽  
Aluminum Honeycomb ◽  
Elastic Plastic Material ◽  
Honeycomb Panel

This paper focuses on the nonlinear dynamics modeling and parameter identification of an Aluminum Honeycomb Panel (AHP) with multiple bolted joints. Finite element method using eight-node solid elements is exploited to model the panel and the bolted connection interface as a homogeneous, isotropic plate and as a thin layer of nonlinear elastic-plastic material, respectively. The material properties of a thin layer are defined by a bilinear elastic plastic model, which can describe the energy dissipation and softening phenomena in the bolted joints under nonlinear states. Experimental tests at low and high excitation levels are performed to reveal the dynamic characteristics of the bolted structure. In particular, the linear material parameters of the panel are identified via experimental tests at low excitation levels, whereas the nonlinear material parameters of the thin layer are updated by using the genetic algorithm to minimize the residual error between the measured and the simulation data at a high excitation level. It is demonstrated by comparing the frequency responses of the updated FEM and the experimental system that the thin layer of bilinear elastic-plastic material is very effective for modeling the nonlinear joint interface of the assembled structure with multiple bolts.

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