About the choice of parameters of the non-linear flexible coupling as damper in two-shaft transport diesel engines

Abstract

The increase in power and speed of modern units with internal combustion engines (ICE) leads to the increase in dynamic loads in them. The effective means of dealing with dangerous torsional vibrations is the introduction of elastic couplings and damping devices, the characteristics of which are most often nonlinear. The features of existing approaches for the choice of their parameters are limited by the imperfection of the models of the devices themselves, the features of the models of machine units with internal combustion engines as multimass systems with several nonlinearities. Goal. The creation of the method for parameters synthesizing of an elastic coupling with a preload as a unit of limiting excessive vibrations in nonlinear models of machine units with twinshaft diesel engines. The following problems should be resolved: the dynamic synthesis problem is formulated as a nonlinear programming problem; a harmonic linearization method was developed for the equations of motion in integral form; the equivalent stiffness and average deformation of the nonlinear connection are determined; an algorithm for finding the vibration amplitudes of nonlinear connections has been created; a reliable nonlinear dynamic model of a machine unit with a 3TD diesel engine has been built; the results of computational studies are compared with experimental data. Methodology. The synthesis method is based on an efficient algorithm for solving analysis tasks. The equations of motion are written in the form of integral equations using the pulsefrequency characteristics of the linearized models. The main advantage of this approach for solving synthesis and optimization tasks is that the number of equations of motion is equal to the number of nonlinearities and the complexity of solving the analysis task is practically independent of the model’s number of degrees of freedom. The problem of dynamic synthesis of coupling parameters is formulated as a nonlinear program-ming task. Results. The parameters synthesis method for the elastic coupling with a preload as a means of limiting excessive vibrations in nonlinear models of machine units with twoshaft diesel engines has been developed. A method of harmonious linearization for the equations of motion in integral form, written using the pulsefrequency characteristics of linearized models, is presented. The task of dynamic synthesis of coupling parameters is formulated as a nonlinear programming task. Originality. The parameters synthesis task of the elastic coupling with a preload is solved as a task of nonlinear programming. An efficient algorithm for solving the analysis task is based on the method of harmonic linearization for the equations of motion in integral form, that are written using the pulsefrequency characteristics of the linearized models. Practical value. The reliable nonline-ar dynamic model of a machine unit with a twoshaft transport diesel engine 3TD has been built. The optimal parameters of the elastic coupling between the engine crankshafts have been determined. The results of computational studies are compared with experimental data.