The compression rebound curve of the gasket can be expressed by the following formula: compression curve: SK=(AC-BCT)DNCK(1) rebound curve: SGSK=AS+BSDGDK(AT+BTT)(2) where: SG is the gasket Compression stress; DG is the deformation amount; SK is the gasket pre-tightening stress; DK is the gasket compression amount when pre-tightening; T is the test temperature; AC, BC, NC, AS, BS, AT, BT are the regression coefficients. Regression analysis of the three gasket test data yielded regression coefficients for equations (1) and (2) as shown.

The relationship between the leak rate and the gasket stress and the medium pressure (sample: wound gasket; test medium: nitrogen; test temperature: 400e) is a typical leakage characteristic curve. The test results show that the leakage rate and the medium pressure are approximately linear, and have the general characteristics of viscous fluid laminar flow; the leakage rate and the gasket compression stress are in a negative exponential relationship, and the larger the compaction stress, the smaller the leakage rate; the leakage rate The temperature increases and the two become exponential. The sealing performance of the gasket can be expressed by the formula (4) L = ALpTMLS-NLG (4) where: p is the medium pressure; AL, ML, NL are the regression coefficients, and these coefficients are listed.

Tightness evaluation block diagram The tightness evaluation of the bolt flange connection is to unify the deformation characteristics and leakage characteristics of the test gasket in the actual connection structure for system analysis, and calculate whether the leak rate of the connection is less than the maximum allowable leak rate, thus connecting The tightness of the situation is evaluated. The specific evaluation methods are: known gasket pre-stress SK, operating pressure p and operating temperature T2, as well as gasket, bolt, flange size and material constant, can be obtained by solving the deformation coordination equation (6) of the bolt flange connection. Gasket working stress SG. By substituting SG, p and T2 into the leakage rate formula (4), the leakage rate under the test conditions can be obtained. L. The leakage rate LR of the actual bolt flange connection can be calculated from the leakage rate correction formula (7). If LR is less than the maximum allowable leak rate Lmax, then the connection is considered to be tight, and vice versa.

Conclusion (1) A modeling method of engine piston-shaft system based on radial basis neural network is proposed. The simulation model of piston-shaft system of single-cylinder engine is established by this method. The effectiveness of the method is verified by verifying the simulation results of a mine engine. (2) The system simulation of the piston-shaft system of the single-cylinder engine is carried out, and the dynamic performance of the piston-shaft system is obtained. The simulation results show that there are nonlinear dynamic phenomena such as limit cycles in the piston-shaft system in the complete working cycle.

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