Study On Contact-Impact Dynamic Response Of The Mechanical System With Elastic Components

Impact is a phenomenon that exists widely in engineering practice. Contact-impact of the mechanical systems is a complicated dynamic response problem. Especially, measurement and analysis of impact force and stress for complex system's impact are always difficult.In this paper, dynamic response property of mechanic system with elastic components is researched by explicit FEA and numerical calculation method. The main work is as follows:At the beginning of the paper, recent developments of column helix spring and contact-impact problems are briefly summarized. Then, considering the object of the paper, FEA is introduced. Load and distortion of the spring is analyzed, the calculation formula of rigidity is educed. Meanwhile, because the rigidity property of springs with big helix angle cannot be solved by the existing theoretical formula, a finite element method is introduced. Combining the theory of mechanics of materials and column helix spring, the single spring ring is simplified and analyzed, the bending speciality of prestressed column helix spring is researched and the relationship between bending moment and bending angle is found, the formula for computing bending angle of the helix spring is obtained, and parameters are optimized. By validating with test, precision of the formula is relatively high. It can be fulfill the requirement of project design, thus laid a foundation on further emulative analysis for dynamics of spring system.A finite element model of the mechanical system is built. Dynamic response of the system with only one prestressed spring when impacting with low speed is researched. The system with two springs when impacting with high speed is researched too. By analyzing and calculating the system impact with rigid body and inelastic body, impact force property, displacement,velocity,acceleration and energy conversion property are educed. Comparing with the results, the differences of them are: continual time of impacting process, the velocity and acceleration of the system after impacting, energy change and so on. Research indicated that impact velocity, impact body's material, impact body's mass, the dimension and material property of structure's support component are main factors result in system's demolition.The research results of this paper show that using explicit finite technique is used to solve contact-impact problems is a high efficiency method and the results of which are relatively accurate and useful to design and optimize the whole system. Meanwhile, conclusions of the paper can also be an important reference for the future research.