A test method for rigid body modal parameters of powertrain mounting system under the condition of complete vehicle

Abstract

The invention discloses a modal parameter test method of a rigid body of a power assembly suspension system based on full-automobile states. According to the test method, a counter-weight based rubber soft hammerhead is used for force hammer excitation and a full-vehicle coordinate system is used as the reference; the X axis points to the back of the vehicle and is perpendicular to the front shaft; the Z axis is upwards vertical; the Y axis is determined according to the right hand rule; the six-degree-of-freedom rigid body modal including translational motions in three directions and rotation around three directions into three groups, and single modal parameter identification is performed on each group once; the specific steps are: selecting X-direction excitation FX of the power assembly, testing frequency response functions of response points and using the PolyMAX modal identification method to identify the X-direction transitional motion modal and rotation modal around the Y axis and the Z axis; selecting Y-direction excitation FY and identifying Y-direction transitional motion modal and rotation modal around the X axis and the Z axis; and selecting Z-direction excitation FZ and identifying Y-direction transitional motion modal and rotation modal around the X axis and the Y axis. According to the invention, the test method is simple to operate, high in identification accuracy and suitable for identification of six-degree-of-freedom modal parameters of the rigid body of any rubber support.

Description

technical field [0001] The invention belongs to the field of automobile loading performance testing, and relates to a testing technology for a power assembly mounting system of an automobile, in particular to a method for testing rigid body modal parameters of a power assembly mounting system in a complete vehicle state. Background technique [0002] Rigid body modal frequency and decoupling rate of automotive powertrain mount system are important parameters for mount system design, and also important evaluation indicators for powertrain vibration isolation performance. [0003] At present, the modal parameters of the vehicle powertrain mount system are mainly based on theoretical calculation and simulation analysis in the early stage of vehicle development. Due to factors such as the manufacturing error of the suspension product and the constraints of the vehicle, there are differences between the theoretical modal parameters and the real modal parameters in the vehicle sta...

AI Technical Summary

Problems solved by technology

There are mainly two types of artificial excitation: vibrator excitation and hammer excitation. With vibrator excitation, the mode of the structure may be essentially affected by the mass and stiffness of the vibrator attachment, and if only one vibrator is used Excitation, if the excitation position is at the node of a certain mode, the mode will be lost in the mode identification

[0006] The artificial excitation modal method mainly has three directions for hammering excitation and single-point hammering excitation respectively. The hammering in the three directions belongs to the multi-reference point hammering technology-MRIT, and the analysis method belongs to the MIMO modal analysis method. The main defect is that the frequency response function data is not collected at the same time, resulting in irrelevant frequency response function consistency, and the reciprocity of the frequency response function is not satisfied

The single-point excitation may have low energy and improper selection of the hammer point position, resulting in the inability to identify the six modes of the rigid body of the powertrain at one time

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