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QUASI-NEWTON WAVEFORM RELAXATION BASED ON energy method

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Journal of Computational Mathematics 2018年第4期36卷 542-562页

作者： Yaolin Jiang Zhen Miao School of Mathematics and Statistics Xi'an Jiaotong University Xi'an 710049 China

A quasi-Newton waveform relaxation （WR） algorithm for semi-linear reaction-diffusion equations is presented at first in this paper. Using the idea of energy estimate, a general proof method for convergence of the continuous case and the discrete case of quasi-Newton WR is given, which appears to be the superlinear rate. The semi-linear wave equation and semi-linear coupled equations can similarly be solved by quasi-Newton WR algorithm and be proved as convergent with the energy inequalities. Finally several parallel numerical experiments are implemented to confirm the effectiveness of the above theories.

关键词： Waveform relaxation Quasi-Newton energy method Superlinear Parallelism

Natural frequency characteristics of thin-walled homogeneous and manifold layered cylindrical shells under pressure using energy method

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Journal of Central South University 2014年第2期21卷 521-532页

作者： M.R.Isvandzibaei Hishamuddin Jamaluddin Raja Ishak Raja Hamzah Faculty of Mechanical Engineering Universiti Teknologi Malaysia

energy method for the vibration of two types of cylindrical shells,namely thin-walled homogeneous isotropic and manifold layered isotropic cylindrical shells under uniform external lateral pressure is *** study is carried out based on strain-displacement relationship from Love's shell theory with beam functions as axial modal function.A manifold layered cylindrical shell configuration is formed by three layers of isotropic material where the inner and outer layers are stainless steel and the middle layer is *** homogeneous cylindrical shell is made-up of isotropic one layer with stainless *** governing equations with uniform external lateral pressure for homogeneous isotropic and manifold layered isotropic cylindrical shells are obtained using energy functional by the Lagrangian function with Rayleigh-Ritz *** boundary conditions that are presented at the end conditions of the cylindrical shell are simply supported-simply supported,clamped-clamped and *** influences of uniform external lateral pressure and symmetrical boundary conditions on the natural frequency characteristics for both homogeneous and manifold layered isotropic cylindrical shells are *** all boundary conditions considered,the natural frequency of both cylindrical shells with symmetric uniform lateral pressure increases as h/R ratio increases and those considering natural frequency of the both cylindrical shells with symmetric uniform lateral pressure decrease as L/R ratio increases.

关键词： cylindrical shell manifold layered pressure energy method

Influence of structure parameters on aeroelastic stability for labyrinth seal based on energy method

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Propulsion and Power Research 2018年第4期7卷 288-295页

作者： Nengmao Wang Yanrong Wang Aimei Tian School of energy and Power Engineering.Beihang University Beijing 100191China Collaborative Innovation Center for Advanced Aero-Engine Beijing 100191China School of Astronautics Beihang UniversityBeijing 100191China

Numerical analysis of turbomachinery based on energy method is used to predict the aeroelastic stability of the straight-through labyrinth seal by solving aerodynamic work and vibration modes has been ***'s found that the increase of pressure ratio leads to the in the circumferential direction of the labyrinth seal corresponds to the number of vibrating nodal *** order to investigate the influence of structure parameters,the effect of relative thickness of the tooth tip,the width of the seal cavity and the eccentricity of the rotor on the aeroelastic stability of the labyrinth seal has been *** result of numerical calculation shows that the change of the structural parameters can affect the aeroelastic stability of the labyrinth seal to a certain extent,and can be applied in the structural optimization.

关键词： Labyrinth seal Aeroelastic stability energy method Nodal diameters Structure parameters

Structural Earthquake Resistance Design Using energy method

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Journal of China University of Geosciences 2003年第2期14卷 166-168页

作者： Hu Rongrong Civil Engineering Department, Huazhong University of Science and Technology, Wuhan 430074 Civil Engineering Department Huazhong University of Science and Technology Wuhan 430074

A summary of status of researches in the field of structural earthquake resistance design on energy concept is presented in three parts: earthquake input, demands on the structure and supplied capacity of the structure. A new approach is proposed for analysis of the seismic response and damage criteria based on the momentary input energy.

关键词： energy method maximum displacement momentary input energy.

energy method in the Safety Assessment of a Building under Workshop Vibration

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International Journal of Plant Engineering and Management 2002年第1期7卷 39-44页

作者： SUN Yong 1, FU Ming fu 1, YANG Guo tai 1, HUANG Ju hua 1, ZHANG Ming hui 2, 1 Nanchang University, 330029 2 Jiangxi Medical Institute, 330006 Nanchang University 3300292 Jiangxi Medical Institute 330006

A Forging machine with its vibration isolation rig, its foundation, and the workshop building constitute a complex non linear dynamic system. The vibration caused by forging, propagating through the ground, will seriously affect the safety of the workshop building. A new kind of energy method is developed for the safety assessment of a building under workshop vibration.

关键词： workshop vibration safety assessment energy method

Study on Theory and Application of the energy method used for Analyzing Compressive Instability in Sheet Forming

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Study on Theory and Application of the Energy Method used fo...

A new method for testing pile by sin- gle-impact energy and P-S curve

第十届国际制造工程与管理会议

作者： XIONG Zhi-qing, XIE Lan-sheng (1. Department of Mechanical Engineering, Nanjing Institute ofTechnology, Nanjing 210013, China 2. College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China)

＜正＞ It is pointed out that there was serious weakness when using the energy method for studying compressive plastic instability in sheet forming in the past. Where applying the deduced instability strengths to relative engineering analysis, theoretical solutions were away from practices. Its basic reason is that simplified process in mathematical analysis of elastic bending energy was completely applied to that of plastic bending energy. Where the camber expressed by function of displacement normal to a plate was approximated to realistic deflective camber, the displacement of deflected plate to compressed direction was neglected. With the aid of the improved insta- bility strengths, the predictions on both critical buckling dimension of blank in cup deep-drawing without blankholder through cylindrical die or conical die and the minimum blankholder pressure to prevent buckling under constant load are universally in agreement with both experimental results and experiential *** the bases of above-mentioned improvement, the approximate expressions for both the curvature and the twist used in equation of the energy of elastic bending are also ameliorated. Thus the obtained general equations for both the energy and the work done by internal force in plastic bending of a plate are more precise than *** the analyses of plastic buckling of shell with bending moment, the effect of bending moment is considered through the work done by simulative bending force. The method proposed in this paper can not only simplify analyses but also get practical result.

关键词： sheet forming deep-drawing buckling energy method

来源： cnki会议评论

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Acta Seismologica Sinica(English Edition) 2004年第z1期17卷 138-149页

作者： XU Zhao-yong(许昭永) DUAN Yong-kang(段永康) WANG Bin(王彬) HU Yi-li(胡毅力) YANG Run-hai(杨润海) XU Jun(许峻) ZHAO Jin-ming(赵晋明) Institute of Disaster Prevention of Yunnan Province Kunming 650041 China Kunming Nanfang Technology and Consultation Company for Rock and Soil Kunming 650091 China

By studying the pile-formula and stress-wave methods (e.g., CASE method), the authors propose a new method for testing piles using the single-impact energy and P-S curves. The vibration and wave figures are recorded, and the dynamic and static displacements are measured by different transducers near the top of piles when the pile is im- pacted by a heavy hammer or micro-rocket. By observing the transformation coefficient of driving energy (total energy), the consumed energy of wave motion and vibration and so on, the vertical bearing capacity for single pile is measured and calculated. Then, using the vibration wave diagram, the dynamic relation curves between the force (P) and the displacement (S) is calculated and the yield points are determined. Using the static-loading test, the dynamic results are checked and the relative constants of dynamic-static P-S curves are determined. Then the sub- sidence quantity corresponding to the bearing capacity is determined. Moreover, the shaped quality of the pile body can be judged from the formation of P-S curves.

关键词： single impact energy method dynamic P-S curves observation of single-pile bearing capacity

Plastic wrinkling model and characteristics of shear enforced Ti-alloy thin-walled tubes under combination die constraints and differential temperature fields

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Chinese Journal of Aeronautics 2016年第6期29卷 1815-1829页

作者： Yan Jing Aeronautical Key Laboratory for Plastic Forming Technology Beijing 100024China Beijing Key Laboratory of Digital Plastic Forming Technology and Equipment Beijing 100024China Beijing Aeronautical Manufacturing Technology Research Institute Beijing 100024China

Plastic wrinkling predictions and shear enforced wrinkling characteristics of Ti-alloy thin-walled tubes under combination die constraints have become key problems urgently in need of solutions in order to improve forming quality in their shear bending processes under differential temperature fields. To address this, a wrinkling wave function was developed by considering their shear bend deformation characteristics. Based on this wave function and the thin shell theory, an energy prediction model for this type of wrinkling was established. This model enables consideration of the effects of shear deformation zone ranges, material parameters, loading modes, and friction coefficients between tube and dies on the minimum wrinkling energy. Tube wrinkling sensitive zones(WSZs) can be revealed by combining this wrinkling prediction model with a thermalmechanical coupled finite element model for simulating these bending processes. The reliability of this wrinkling prediction model was verified, and an investigation into the tube wrinkling characteristics was carried out based on the experimental conditions. This found that the WSZs are located on either a single side or both sides of the maximum shear stress zone. When the friction coefficients between the tube and the various dies coincide, the WSZs are located on both *** larger the value of the tube inner corner radius and/or the smaller the value of the outer cornerradius, the smaller the wrinkling probability. With an increase in the value of the moving die displacement, the wrinkling probability increases at first, and then decreases.

关键词： Combination die constraint Differential temperature field energy method Finite element Shear bending Ti-alloy thin-walled tube Wrinkling

ON THE EVOLUTION OF LARGE SCALE STRUCTURES IN THREE-DIMENSIONAL MIXING LAYERS

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Acta Mechanica Sinica 2001年第1期17卷 10-23页

作者：罗纪生 Department of Mechanics Tianjin University Tianjin China 300072

In this paper, several mathematical models for the large scale structures in some special kinds of mixing layers, which might be practically useful for enhancing the mixing, are proposed. First, the linear growth rate of the large scale structures in the mixing layers was calculated. Then, using the much improved weakly non-linear theory, combined with the energy method, the non-linear evolution of large scale structures in two special mixing layer configurations is calculated. One of the mixing lavers has equal magnitudes of the upstream velocity vectors, while the angles between the velocity vectors and the trailing edge were pi /2 - phi and pi /2 + phi, respectively. The other mixing layer was generated by a splitter-plate with a 45-degree-sweep trailing edge.

关键词： mixing layer large scale structure modified weakly non-linear theory energy method passive control