| Large mechanical products were used in all sectors of the national economy widely, and their reliability, economy and safety are symbols of development level of state mechanical industry. At present, situation of safe production is still severe. As a result of large equipment fault, serious accidents that cause heavy economical loss, even personal injury and death, are too numerous to enumerate. At the same time, the competition among manufacturing market becoming more and more severe, the cycle of design, test, production and occupying market are key factors impacting on survival and development of relative enterprises. How to design economical and reliable mechanical products agilely and quickly is always very important matter to scientific and technical personnel in engineering.Reciprocating compressor has many merits, such as its pressure range is wide, thermal efficiency is high and applicability is better etc, so it is indispensable equipment in petroleum exploitation and chemical synthesis fields. Presently the problems for reliability, economy and flexibility of reciprocating compressor product become increasingly outstanding, because of its large structure, long design period and high manufacturing cost etc. Furthermore because more of these mechanical products are small-batch, even single production, it is very difficult to go on research on large sample test; at the same time, demands of users are changeful constantly, so rapid reaction to the market is very necessary. Therefore it has practical significance that study on reliability evaluation, agile design and virtual test about reciprocating compressor.The paper regards large reciprocating compressor as study case, combine reliability theory with compute technology, put forward the concept of digital study to go on research on analysis, design and simulation of mechanical products; at the same time, the paper improved on the part structure of reciprocating compressor based on research, and methods of theory calculation and simulation analysis were used to verify rationality and validity of improved structure. The detail contents of the paper are as following:(1) The paper developed a program platform for design calculation of reciprocating compressor. The platform can go on complicated thermodynamics and dynamics calculation handily, and get all kinds of design data and load graphs rapidly and accurately using VC++ and Matlab software, and provide basis for checking strength of key parts and building systems of design and simulation.(2) The paper developed a program platform for reliability sensitivity analysis of key parts. Based on reliability theory and considering various influencing factors (such as size tolerance, material property and machining process etc) completely, the paper built mathematic models of strength reliability analysis of key parts; and come true visualized and programmed course of analysis using VC++6.0. The platform can quantitatively provide scientific and accurate data of estimation reliability of key parts through probability; and give study on the influence of various factors on reliability, and provide theoretical basis for determining and controling design parameters reasonably.(3) The paper developed a software system of parametric design of reciprocating compressor. The software system received all determined design information coming from design calculation platform and reliability analysis platform to construct and modify 3-D models of parts and product rapidly and regenerate relative working drawings based on Pro/E and Pro/TOOLKIT. So it can improve design efficiency greatly and avoid the phenomena of information loss in human design. At the same time, the paper combined LAYOUT function of Pro/E with its second development technology, and solve the problem of parametric design for assemble models successfully, and come true intelligent and agile design of mechanical products indeed.(4) The paper developed a software system of virtual reliability test of reciprocating compressor. The designed 3-D models of parts, ANSYS/LS-DYNA, APDL and VC++ were used to build system platform of virtual test. Considering the influences of machining tolerance and property randomness of material on life reliability of mechanical system, dynamic virtual simulation of transmission mechanism of compressor was done and virtual test data of key parts was got; distribution type of data was analyzed and reliability of key parts was calculated to estimate reliability of whole transmission system. Moreover response surface method was used to go on study of virtual test on piston rod of compressor to solve the problem for strength analysis of multi-factors coupling action structure, and sensitivity of various influencing factors were analyzed, and reliability of structure was calculated to direct real design work.(5) The paper proposed the improved measure on thread connector of piston rod of reciprocating compressor. Based on the result of above study and pointed to the facts that piston rod always causes fatigue fracture, the improved method of structure was proposed. Moreover it was verified that the improved method of structure can improve fatigue life of piston rod greatly with theory calculation combining simulation analysis of ANSYS.
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