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Static response analysis of structures with interval parameters using the second-order Taylor series expansion and the DCA for QB 被引量:3
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作者 Qi Li Zhiping Qiu Xudong Zhang 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第6期845-854,共10页
In this paper, based on the second-order Taylor series expansion and the difference of convex functions algo- rithm for quadratic problems with box constraints (the DCA for QB), a new method is proposed to solve the... In this paper, based on the second-order Taylor series expansion and the difference of convex functions algo- rithm for quadratic problems with box constraints (the DCA for QB), a new method is proposed to solve the static response problem of structures with fairly large uncertainties in interval parameters. Although current methods are effective for solving the static response problem of structures with interval parameters with small uncertainties, these methods may fail to estimate the region of the static response of uncertain structures if the uncertainties in the parameters are fairly large. To resolve this problem, first, the general expression of the static response of structures in terms of structural parameters is derived based on the second-order Taylor series expansion. Then the problem of determining the bounds of the static response of uncertain structures is transformed into a series of quadratic problems with box constraints. These quadratic problems with box constraints can be solved using the DCA approach effectively. The numerical examples are given to illustrate the accuracy and the efficiency of the proposed method when comparing with other existing methods. 展开更多
关键词 Interval parameters · Second-order Taylorseries expansion · Static response of uncertain structures quadratic programming problems · DCA
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From the Big Bang to the Big Rip: One Cycle of a Closed Granular Friedmann-Planck Universe 被引量:1
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作者 Raymond Fèvre 《Journal of High Energy Physics, Gravitation and Cosmology》 2021年第2期377-390,共14页
The first part of this article develops [1] a closed universe model deploying by identical multiplication a Friedmann-Planck micro-universe;thus this one constitutes the grains of the vacuum of this universe. The quan... The first part of this article develops [1] a closed universe model deploying by identical multiplication a Friedmann-Planck micro-universe;thus this one constitutes the grains of the vacuum of this universe. The quantum initial expansion of this is quadratic as a function of time. Using this model, calculating the density of matter at the present time gives a correct numerical result. The essential point is that during periods of expansion following the initial quadratic period, this model reveals a surprising phenomenon. The function expressing the radius curvature as a function of time depends on the individual mass of the heaviest elementary particles created at the end of the quadratic period. The model also leads to reflection on the dark matter. The second part imagines a new type of Big Rip based on the following hypothesis: when the acceleration of the Universe, caused by dark energy, reaches the value of Planck acceleration, destruction of the microscopic structure of the Universe occurs and is replaced by a macroscopic structure (photon spheres) identical to that of the initial Planck element. Thus a new Big Bang could begin on an immensely larger scale. This reasoning eventually leads to reflection on the origins of the Big Bang. 展开更多
关键词 Big Bang Big Rip Friedmann Universe Planck Scale Dark Energy Dark Matter quadratic expansion COSMOLOGY Quantum Gravity
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