The sealing screw is the key connecting part of the cylinder. Its reliability and parameters directly affect the working of the cylinder and the mechanism and the main machine. The reliability and the size of the part. The design of the previous cylinder sealing screw is designed according to the conventional safety factor method. The working stress intensity is regarded as a certain amount, so the designed screw diameter is often too large. In fact, due to various factors, the stress and strength of the screw are not certain, but random variables or fuzzy variables. Therefore, it is necessary to use fuzzy probability design theory to explore the fuzzy probability design method of sealing screws.
1 Fuzzy Probability of Sealing Screws Designing Fuzzy Subsets and Probabilistic Fuzzy Subsets of Fuzzy Events 4 is a membership of a domain on the membership of the mountain.
On the universe, if fuzzy subset 4 is a random variable, then 4 is called a fuzzy event. The probability of the fuzzy event is defined as the stress cylinder between the cylinder and the cylinder head is connected by a pre-tightening screw set with pre-tightening force and axial variable load. In order to ensure reliable sealing, it has tight requirements.
Assume that the tensile stress of each screw is evenly distributed along the cross section. However, due to the variability of the dynamic stress concentration factor and geometrical dimensions of the load distribution, the stress values ​​of each screw in the screw group are different, but are normally distributed. The mean and standard deviation are determined as follows: the mean value of the maximum working load of each screw, the average value of the inner diameter of the cylinder; the number of screws in the set of screws.
The mean value and standard deviation of the stress caused by the working load of each screw are respectively 6 working load coefficient of variation. The pre-tightening force of the screw will also cause the pre-tightening stress. Therefore, the mean value of the total tensile stress distribution of the screw and the standard deviation are 1 respectively. Pre-tightening stress normal distribution mean value, desirable, fuzzy fuzzy yield limit> Screw connection with tightness requirement, the failure form is the yield of the screw, and in its failure criterion, 7 the yield limit 7 is a fuzzy concept, for example, If we specify 7=640 with a screw rating of 8.8, there is an intermediate transition between the screw stress on the screw and the total allowable use. When considering this process, 7 becomes a fuzzy concept, and its boundary is a fuzzy boundary, which is difficult to give with a certain value. Therefore, we treat it as a fuzzy variable, and its membership function can be described by the fuzzy reliability of the above-mentioned available cylinder sealing screw. The juice criterion is that the probability that the fuzzy yield limit of the screw material is greater than the screw stress must be greater than or equal to the fuzzy reliability scale required by the design. As described in 12, the stress follows a normal distribution, and the probability density function is the membership function of the intensity. For the type 8 and the substitution of the two types of the 89 type into the type 2, the fuzzy reliability scale of the screw is not known to be the failure of the yielding cylinder. The inner diameter of the loading cylinder of the brick wall testing machine is known to be 5.14,376, and the fuzzy reliability is sought.
67 two types of strength, the selected screw performance level is 8.8, its yield limit 7 = 6 according to the amplification factor method in the formula 8, =! . =, so that the membership function of the fuzzy yield limit of the screw is 10 formula fuzzy reliability scale = 0.99999.
For the sealing screw of the example given in this paper, if the conventional design method is used, the diameter of the sealing screw can be known. The calculated value of the thread diameter of the fuzzy probability design is much smaller than that of the conventional juice setting.
3 Conclusion Fuzzy reliability design can reduce the diameter of the screw under the premise of fully satisfying the reliability requirements. This is because it considers the discreteness of stress and the ambiguity of strength, making its design more reasonable and economical.
The conventional design method has no accurate accuracy for the screw connection, and the fuzzy reliability design method can quantitatively and speculate the safety and reliability of the sealing screw. The method can be used for the design of ten other hydraulic components, such as the design of the hydraulic cylinder. The design of the flow valve regulating spring and so on.
Wang Caiqi's Methodology of Fuzzy Theory, China Building Industry Press, 1988, Zhi Zhizhong, Reliability Design of Mechanical Parts, Mechanical Industry Press, 1988, Lin Guoxiang, Discular Spring, Fuzzy Reliability Optimization Design. Mechanical design, 19956 Northeast Institute of Technology and other mechanical parts design manual, metallurgical industry publication received time 1999 up to the 15th page of the size of the size of the coordinate range and the grid frame shape length and width ratio examples, etc., and Actual double ordinate labeling and other functions.
Dynamic performance affects 81 simulation results, such a 1 original can not be drawn.
Processing research. In short, the application of electronic grid software to process 051 dynamic simulation results can give full play to the dynamic simulation of hydraulic systems, and reveal the physical meaning of the simulation results.
Digital Simulation Method for Dynamic Process of Lu Yongxiang Hydraulic Transmission and Control System Laboratory of Fluid Transmission and Control, Zhejiang University, 1982.1 Yu Kaiyuan Application of DSH Program System for Hydraulic System Dynamic Imitation t Hydraulic Engineering Manual, Lei Tianjue, Editor, Mechanical Industry Press, 1990.4 4 Huang Yong, hydraulic system dynamic simulation software DSH and electronic grid software portal and its algorithm and human-machine interface improvement Southeast University master degree theory 4 conclusion sub-grid software replaced the original redundant version 1 paragraph 1 painting module 03 people. This study violates the format conversion of the two simulation files from the 1 simulation data result file to the electronic grid software input file conversion.
Therefore, the electronic grid software can be used to draw a beautiful and flexible simulation curve that can be arbitrarily modulated; in the same way, several simulation result curves after changing the parameters can be drawn, so that the effect of the parameter change on the dynamic performance of the system can be more easily compared; The test results of the data acquisition are compared with the simulated nodules in the same curve. The internal function of the electronic grid software can also be used to make the first set of simulation results. The rolling mill rolls are successfully developed in China. The current set is composed of Haibao Steel Group and Xingtai Roll Co., Ltd. jointly developed a pair of cross-rolling mill supporting rolls, which was successfully developed in Xingtai Machinery Roller Group Co., Ltd., which is controlled by Xingtai Machinery Co., Ltd. The squatter, the matching unit of the 580 hot strip mill, is the first set of plate-type controlled hot rolling mills with international advanced level introduced in China in the 1990s. After trial and rolling use, the technical performance indicators have reached the level of similar foreign products. The successful development of this product and the formation of mass production not only filled the gaps in the national project, but also saved a large amount of purchased funds for Shanghai Baosteel Group.
Sun Fu
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