42results about How to "Make up for and perfect limitations" patented technology

The invention discloses a beam structure non-probabilistic reliability solving method capable of considering multi-failure modes. The correlation of two failure models including strength and rigidity is considered; firstly, existing multisource uncertain factors in material characteristics, environment external loading and the like are fully considered, interval mathematics and fuzzy mathematics are adopted to carry out quantization on the multisource uncertain factors and develop propagation analysis; then, the multisource uncertain factors are introduced into a general reliability solving theory, the non-probabilistic reliability solving method is developed, and on the basis of the method, the strength and rigidity reliability degree analysis of a beam structure can be independently carried out; and finally, the correlation of two failure models is comprehensively considered, a correlation constitutive relation equation is established, and the reasonable representation of the correlation among failure modes is realized. The method gives the comprehensive influence on structural strength reliability by different failure modes, can realize the comprehensive optimization design of the structural strength, and guarantees that the design gives consideration to safety and economy.

The invention discloses an active control method of structural vibration based on non-probability interval confidence reliability, wherein an automatically adjustable active vibration control system is designed, aiming at the uncertainty of structural parameters, in the original open-loop control system Based on the improvement, based on the calculation method of the dual reliability index of reliability and confidence, on the basis of the original basis, the research on the vibration suppression algorithm is carried out under the premise of the uncertainty of the structural parameters, and the confidence index is introduced to make the designed The self-adjusting active vibration control system can improve the reliability of the structure. The feasibility of the automatically adjustable active vibration control system proposed by the present invention is verified by using a continuous model and a discrete model, and this control method can be used in the design of active control systems of uncertain structures in the future.

The invention discloses an existing structure static equivalent reliability evaluation method based on an interval set envelope function. The method comprises the steps that the envelope function is introduced into the reliability problem of a dynamic structure, a failure domain of the multi-parameter structure uncertainty changing along with time is approximately constructed through an envelope surface, a dynamic problem is transformed into a static problem, and effective evaluation on the structural security situation is achieved through reliability degree index calculation. According to the method, a partial differential equation is defined according to the character that the envelope surface in the internal set envelope function is tangent to a failure boundary hypersurface continuously changing along with time, and a risk moment corresponding to an extension point is solved; a limited dimensional static failure domain equivalent to an original dynamic problem at a limited risk moment is obtained by building a multi-dimensional hypercube model containing the correlation; the static equivalent reliability degree calculation process of an existing structure is finally achieved on the basis of a volume ratio idea, and the traditional time-varying reliability calculation scale is greatly reduced while the precision is guaranteed.

The invention discloses a method for analyzing the vibration of an orthotropic simply supported rectangular thin plate with opposite sides. This method is based on the free vibration equation of an orthotropic rectangular thin plate. Firstly, the mode differential equation is established, and the Hamiltonian canonical equation is constructed. Secondly, according to the symplectic geometry method, the separation of variables method is used to solve the problem, and the corresponding The expressions of the eigenvalues ​​of the two groups of eigenvalues ​​were analyzed; the general solution form of the mode shape function with undetermined constants was constructed, and the expressions of the eigenvalues ​​and their eigenvectors were derived by combining the simply supported boundary conditions on opposite sides , and proved the symplectic orthogonality and completeness of the eigenvector system; using the symplectic eigenvector expansion, the expression of the state vector was obtained, and then the general solution of the mode shape function was obtained; finally, for the six common Boundary conditions, the corresponding frequency equations were derived respectively, so as to realize the accurate solution of the free vibration frequency, which can lay the foundation for the development of its dynamic analysis and related applications.

The invention discloses an estimation method for a sound vibration fatigue life containing an uncertain metal structure.According to the method, firstly, a finite element analytical model of a metal structure is established, the uncertain effect of material and structure characteristic parameters under finite sample conditions is considered, and a systematic transfer function is obtained based on the frequency response analytical theory; secondly, according to the characteristics of random noise loads, a mean square root response and stress power spectral density function (PSD) of displacement and stress of all key nodes is obtained through an SRSS method for typical broadband steady ergodic random noise loads; thirdly, in combination with a Dirlik model, an interval uncertain propagation second-order Taylor series expansion method and an analytical method for vibration fatigue within a frequency domain, the relation between a rain flow amplitude probability density function and the power spectral density function is set up; finally, the Miner linear accumulative damage theory is used for obtaining an interval range of the sound vibration fatigue life containing the uncertain metal structure.Dispersity of the structure and material parameters is taken into full consideration during calculation of the structural life excited by typical random noise, and therefore the obtained fatigue life is more reasonable.