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Technical Paper

An Improved K-Means Based Design Domain Recognition Method for Automotive Structural Optimization

2018-04-03
2018-01-1032
Design optimization methods are widely used for weight reduction subjecting to multiple constraints in automotive industry. One of the major challenges is to search for the optimal design in an efficient manner. For complex design and optimization problems such as automotive applications, optimization algorithms work better if the initial searching points are within or close to feasible domains. In this paper, the k-means clustering algorithm is exploited to identify sets of reduced feasible domains from the original design space. Within the reduced feasible domains, the optimal design can be obtained efficiently. A mathematical example and a vehicle body structure design problem are used to demonstrate the effectiveness of the proposed method.
Technical Paper

The Design Optimization of Interior Noise in Vehicle Based on Response Surface Method

2015-06-15
2015-01-2242
The design optimization of vehicle body structure is addressed to reduce interior noise and improve customer satisfaction in this paper. The structural-acoustic model is established and the response of sound pressure in frequency domain is obtained by using finite element method. The minimization of sound pressure near the driver's right ear depends on the geometry of vehicle body structure and the layout of damping treatments. The panel participation analysis is performed to find out the key panels as design variables and improve the efficiency of optimization computation. Response Surface Method (RSM) is utilized to optimize the vibro-acoustic properties of vehicle body structure instead of complex structural-acoustic coupling finite element model. Geometric optimization problem of panels is described and solved to minimize the interior noise in vehicle.
Technical Paper

Test Method, Simulation and Micro-process Dynamic Model for Noise Analysis of Auto Hydraulic Shock Absorber

2015-06-15
2015-01-2351
In order to measure the noise of auto shock absorbers, a test bench used to detect piston-rod vibration responses of shock absorbers and measuring analyzer named SANTS-I were developed. The vibration response data was detected by bench tests, which shows that there are high-frequency violent peaks on the sine curve of piston-rod oscillating with relative low frequency. In order to explain the interior work dynamic mechanism of shock absorbers, a schematic Micro-process Dynamic Model with 10 steps particularly divided extension and compression stroke in more detail, and dynamic differential equations for each step were presented and discussed. Furthermore, numerical simulation for the inner impacts interaction between piston and damping fluid of hydraulic shock absorber was realized by ADINA software, by the establishment of a gas-liquid two-phase finite element model.
Technical Paper

A Simplified Three-Dimensional Finite Element Model of Serpentine Belt and its Application into a Belt Driving System

2015-04-14
2015-01-0451
The serpentine belt's multi-scale problems in geometric size, which gives rise to a very large number of element and deeply low calculating efficiency, always bring obstacles when predicting the dynamic response of a serpentine belt driving system using three-dimensional finite element model (FEM). In this paper, a simplified finite element model is built which can accurately present the original serpentine belt's geometric characteristics such as cross-area and moment of inertia, as well as material characteristics such as stiffness and damping, etc. This simplified model is then used in a three-dimensional belt-drive model to simulate the dynamic characteristics of the belt-drive system. The results show that the tension fluctuation for the original serpentine belt and the simplified belt are in good agreement with each other which confirms that the simplified belt model can be used to predict the engine front end accessory drive system (EFEADS)'s dynamic characteristics.
Technical Paper

The Design Optimization of Vehicle Interior Noise through Structural Modification and Constrained Layer Damping Treatment

2015-04-14
2015-01-0663
The design optimization of vehicle body structure is addressed to reduce interior noise and improve customer satisfaction in this paper. The structural-acoustic model is developed by using finite element method. The frequency response of structural-acoustic system is computed by modal analysis method. The optimization problem is constructed to minimize the sound pressure level in the right ear of the driver. The sensitivity analysis is carried out to find the key panels to be optimized as design variables and improve the efficiency of optimization computation. Response Surface Method (RSM) is utilized to develop the surrogate model and optimize the vehicle Noise Vehicle and Harshness (NVH) behavior. A 9dB reduction of sound pressure level (SPL) in the right era of the driver is obtained through geometric optimization for panels. Furthermore, the topology optimization model is developed to search the optimal layout of constrained layer damping treatments in the front floor.
Technical Paper

Design Optimization of Vehicle Body NVH Performance Based on Dynamic Response Analysis

2017-03-28
2017-01-0440
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.
Technical Paper

Measurements of the Evaporation Behavior of the Film of Fuel Blends

2018-04-03
2018-01-0290
The formation of fuel film in the combustion cylinder affects the mixing process of the air and the fuel, and the process of the combustion propagation in engines. Some models of film evaporation have been developed to predict the evaporation behavior of the film, but rarely experimental results have been produced, especially when the temperature is high. In this study, the evaporation behavior of the film of different species of oil and their blends at different temperature are observed. The 45 μL films of isooctane, 1-propanol, 1-butanol, 1-pentanol, and their blends were placed on a quartz glass substrate in the closed temperature-controlled chamber. The shape change of the film during evaporation was monitored by a high-speed camera through the window of the chamber. First, the binary blends film of isooctane and one of the other three oils were evaporated at 30 °C, 50 °C, 70 °C and 90 °C.
Journal Article

Interaction of Gear-Shaft Dynamics Considering Gyroscopic Effect of Compliant Driveline System

2015-06-15
2015-01-2182
Due to the design of lightweight, high speed driveline system, the coupled bending and torsional vibration and rotordynamics must be considered to predict vibratory responses more realistically. In the current analysis, a lumped parameter model of the propeller shaft is developed with Timoshenko beam elements, which includes the effect of rotary inertia and shear deformation. The propeller shaft model is then coupled with a hypoid gear pair representation using the component mode synthesis approach. In the proposed formulation, the gyroscopic effect of both the gear and propeller shaft is considered. The simulation results show that the interaction between gear gyroscopic effect and propeller shaft bending flexibility has considerable influence on the gear dynamic mesh responses around bending resonances, whereas the torsional modes still dominate in the overall frequency spectrum.
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