Multi-body Dynamics Simulation Of Crankshaft System On 4DC Diesel Engine

The crankshaft is one of the most important components of engine, it endures complex loads and it is the key point and difficulty of the engine design. The traditional design and analyze methods are so simply that they can not be satisfied with the actual demands. The Multi-body system Dynamics and the finite element analysis make precise analysis of crankshaft being true.A method that combined finite element method with multi-body dynamics simulation is applied to carry on dynamics analysis simulation on the 4DC diesel engine crankshaft system in this article. Its main research content is: Establishes reasonable diesel engine crankshaft system dynamics model, completes the simulation in an action cycle, and obtains the power response characteristic which displays in one operation cycle, simultaneously carries on the crankshaft torsional vibration analysis, the bearing load analysis, obtains the minimum oil film thickness, the peak oil film thickness and so on. Then, it carries on the transient dynamics analysis on crankshaft using finite element analysis software. It can clearly show the stresses and strain in each part of the crankshaft, and we can rapidly find the dangerous spot. It has provided the powerful technical guarantee for precisely dynamics simulation of crankshaft, and the innovation design, the modification design and the optimized design.First, in view of the concrete product unique features as well as the following functional analysis characteristic simplify the crankshaft system. Delete some small fillet (bevel edge) and the thin oil hole (oil passage) and some geometry characteristic. Create three-dimensional solid model using modeling software Pro/E.Next, selects the suitable unit type and the unit size according to analyzes needs to discretize the structure, assigns different grids in different districts, thus controls the certain grid density from the overall and may guarantee the model automatic separate reliability, guarantees the computed result to be able the real reflection of the crankshaft modal analysis. And the modal test has confirmed the accuracy of computed result.After finishing the finite element model, defines the main degree of freedom nodes using the substructure analysis method. The main degree of freedom nodes take the structure dynamic rigidity and the material damping in account. For this crankshaft, it defines 5 main degrees of freedom nodes on each main journal, which distribute within the effective width of main bearing shell. Two other...