Marine Outboard Two-throw Crankshanft Dynamics Simulation And Reliablity Study

Outboard engine crankshaft is the main core component of the engine. Its role is to transform the burst energy generated by each cylinder fuel, through the reciprocating motion of the pistons and connecting rods, to the rotary form and transmit it to the propeller, so as to promote the ship forward. In the actual work process, the periodic vibration loads and shock loads can result in the crankshaft’s fatigue failure and accidental breakage. Meanwhile, because the crankshaft work enclosed in the internal engine, the destruction features latency and abruptness. Once the crankshaft failure happens, the ship may lose power during the voyage, causing serious consequences. How to ensure the safety and reliability as it works? It require us to do a full demonstration and analysis on the performance of the crankshaft during products’ primary development, and get a comprehensive understanding of its running state and dynamic characteristics, in order to guide practice, improve production, and design qualified products.This topic is one of the research directions of "technology research of Marine Outboard crankshaft precision forging technology and reliability", which is derived from the Ministry of Science and Technology’s "scientific and technical personnel serve companies Action project"(project number:2009GJC30031), which is applied for and presided by Professor Yu. That is to study Marine Outboard Crankshaft dynamics simulation and reliability. This topic has a great practical significance to verify the security of the crankshaft in terms of strength and reliability.1. The essay makes a review aming at the research field of the crankshaft simulation and reliability and the latest progress, analyses the current research results and inadequacy and discusses the significance of crankshaft system dynamics and reliability study.2. The essay, using the outboard crankshaft system as the study target, theoretically analyses shaft kinematics and dynamics characteristics, establishes the corresponding mathematical models, and get the motion and force law of the crankshaft system.3. Combining their respective characteristics and advantages of CATIA, ANSYS and ADAMS, the essay establishes the flexible crankshaft simulation model in ADAMS,and then carries out the outboard engine crankshaft system dynamics simulation under rated load, and demonstrates the design size of crank linkage component parts is reasonable and non-interference.4. Through the analysis of simulation results, the essay gets the main journal axis of motion parameters and crank pin load. And through the analysis of kinetic data processing, there is a close correspondence between the dynamic response characteristics demonstrated by the crankshaft running with the applied external load. Find the dangerous section of the crankshaft failure, according to the kinetic analysis.5. Based on the simulation, the essay using the stress-strength interference model of the reliability theory and theories of simply supported beam and material mechanics, and then completes statistics of the stress and strength distribution of the crankshaft. The calculation results show that the outboard engine crankshaft’s strength meets the design requirements with high reliability.