Study On The Torsional Vibration-absorbed Mechanism And The Matching Simulation Technology Of The Diesel Silicone-oil Damper

The torsional vibration of the diesel shaft sysytem inevitably exists when the diesel engine running, if this harmful vibration not suppressed, the machinery equipment is not working properly, even lead to the fatigue failure of the diesel engine shaft especially for the heavy-vehicle diesel engine used in the heavy transport and construction machinery vehicles, highly pressurized, high-speed characteristics, often the same volume of diesel engine’s load compared the previous model has been increased several times.the more its own strengthen indicators is improved,the more the shafting torsional vibration is inevitably serious. Installing the torsional vibration damper is the main way to reduce the diesel engine shafting torsional vibration, the torsional vibration damper reasonably designed and matched,has a very important significance to reduce the diesel engine shafting torsional vibration amplitude, to avoid the torsional vibration hazards, to reduce the noise and improve the vehicle comfort.The silicone-oil dampers are simple-structure and high efficiency relative to the other structures of the shock absorber used in the diesel engine shafting torsional vibration-absorted aspect. But the slicone-oil dampers did not keep up with the pace on the development of the modern diesel engine technology, the matching design and calculation of the torsional dampers currently mainly follow the previous theoretical and empirical formula (B.I.C.E.R.A), it is lack of the reliable computing method to the damper matching design, to match the shock absorber with the original design method does often not have the desired damping effect.The development of the modern diesel engines, however, requires the carrying capacity of a high enough reliable shock absorber. Therefore, to do in-depth and meticulous research on the torsional dampers matching calculation and design methods has great valueble in the engineering application. This topic is intended to the rheology of the polymer materials, the non-Newtonian fluid mechanics, thermodynamics, vibration mechanics and diesel engine dynamics as the theoretical basis, the silicone-oil on top of the rheological properties of the experimental study, the actual work characteristics, the combined with the torsional dampers for the damping Mechanism analysis and the research, to establish the diesel engine dynamic equilibrium match of the damper,to form a more accurate and reliable matching calculation and optimization of the the design method based on the non-Newtonian fluid. Also taking advantage of the existing three-dimensional modeling by the multi-body dynamics and the finite element simulation software, to provide of the diesel crankshaft multibody dynamics systems and the torsional dampers torsional vibration simulation-based method for the practical engineering application, as an adjunct of the product design verification, to shorten the product development cycle. The main work of the paper is as follows:1) Based on the non-Newtonian fluid mechanics, rheology, thermodynamics, vibration mechanics, Accoding to the silicone-oil rheological test instrument with the advanced extension rheometer, to construct the silicone-oil fluid mechanics model and this constitutive equation.2) On the basis of the study of the mechanical properties of the silicone-oil damper combined with the diesel engine crankshaft torsional vibration principle, to construct the calculation method to the damping coefficient, the viscous friction moment, the heat production and heat dissipation about the damper.3) In the study on the basis of the silicone-oil damping mechanism, combined with the silicone-oil shock absorber works, through the analysis of the damper temperature to affect their work performance, speed rate, silicone-oil viscosity, and the vibration amplitude at the same time the parameters such as the intrinsic Contact the study simulated damper thermal balance established the process numerical methods, the establishment of a dynamic balance of operating conditions close to the actual damper matching calculation method to improve the accuracy and efficiency of/the matching calculation.4) To construct the three-dimensional model of a diesel engine crankshaft system and themulti-body dynamics model, then set the boundaries and constraints, do the simulation calculation, to get the instantaneous speed of the diesel engine crankshaft system for the spectral analysis, and the torsional vibration calculation analysis of the crankshaft system.5) From the silicone-oil damper structural features and design requirements, regardless of the dynamic performance, the economy and reliability factors, the establishment of a multi-objective optimization of the torsional vibration damper design models,to construct a multi-objective optimization model, using the genetic algorithms for the design optimization,to achive the optimization of the main parameters damper system configuration, in order to achieve the integrated optimal performance of its products.6) Through The diesel engine bench test, to get the shafting torsional vibration amplitude and the torsional dampers surface temperature, can verify the accuracy of the matching simulation method.