Derivation of Empirical Compliance Equations for Circular Flexure Hinge Considering the Effect of Stress Concentration

Tie-Min Li,Jing-Lei Zhang,Yao Jiang 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

This paper presents the compliance modeling of circular flexure hinge. The calculation accuracies of several compliance equations are firstly compared with the finite element analysis (FEA) results. Then the influences of the stress concentration on the compliance calculations of the flexure hinge are analyzed systematically. It shows that the stress concentration has great influence on the axial compliance calculation. Utilizing the exponential model, empirical compliance equations of circular flexure hinge are derived, and the influences of the stress concentration on the axial compliance are considered. These empirical compliance equations are verified to be with high calculation accuracy for a wide range of t/R ratios. Finally, the empirical compliance equations are utilized to analyze the compliance and displacement amplification ratio of a bridge-type compliant amplifier. The results are compared with FEA software, and it proves the accuracy and effectiveness of these empirical equations once again. In addition, the modeling method presented in this paper is general and can also be applied to the compliance equations derivation of other types of flexure hinges.

Dynamic analysis method for the progressive collapse of long-span spatial grid structures

Li-Min Tian,Jian-peng Wei,Ji-Ping Hao,Xian-tie Wang 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.23 No.4

In the past, the progressive collapse resulting from local failures during accidents has caused many tragedies and loss of life. Although long-span spatial grid structures are characterised by a high degree of static indeterminacy, the sudden failure of key members may lead to a catastrophic progressive collapse. For this reason, it is especially necessary to research the progressive collapse resistance capacity of long-span spatial grid structures. This paper presents an evaluation method of important members and a novel dynamic analysis method for simulating the progressive collapse of long-span spatial grid structures. Engineering cases were analysed to validate these proposed method. These proposed methods were eventually implemented in the progressive collapse analysis of the main stadium for the Universiade Sports Center. The roof of the structure was concluded to have good resistance against progressive collapse. The novel methods provide results close to practice and are especially suitable for the progressive collapse analysis of long-span spatial grid structures.

Viscosity methods of approximation for a common solution of a finite family of accretive operators

Jun-Min Chen,Li-Juan Zhang,Tie-Gang Fan 영남수학회 2011 East Asian mathematical journal Vol.27 No.1

In this paper, we try to extend the viscosity approximation technique to find a particular common zero of a finite family of accretive mappings in a Banach space which is strictly convex reflexive and has a weakly sequentially continuous duality mapping. The explicit viscosity approximation scheme is proposed and its strong convergence to a solution of a variational inequality is proved.

Output decoupling modeling of a XY flexure-based compliant manipulator

Yunsong Du,Tie-Min Li 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.1

This paper presents the coupling stiffness modeling of an XY flexure-based manipulator. Stiffness/compliance equations for compliant mechanisms are first obtained. According to a simplified spring model, the input stiffness and coupling stiffness of the proposed manipulator consisting of outer and inner kinematic chains are then derived. This simplified spring model is composed of four parallel chains, such as the left, lower, upper and right parallel chain. Subsequently, the external force/moment and the output displacement of the manipulator are analyzed by using finite element analysis (FEA). Finally, a prototype of the manipulator is fabricated. Its motion range and the corresponding cross-coupling displacements are measured, and thus the cross-coupling ratios can be derived. It demonstrates that the manipulator possesses good decoupling characteristic, and the proposed theoretical model is reasonable and accurate.

Counterweight optimization of an asymmetrical hybrid machine tool based on dynamic isotropy

Jun Wu,Tie-Min Li,Liping Wang 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.7

This paper deals with the counterweight optimization of an asymmetrical hybrid machine tool based on dynamic isotropy. The dynamic model is derived and the dynamic manipulability ellipsoid is studied. Based on dynamic manipulability ellipsoid, the dynamic isotropy is defined. Counterweight block and fluid counterweight are presented to balance the weight of moving parts. The mass of the counterweight block is optimized to obtain the maximum dynamic isotropy in the workspace. The dynamic isotropy of the machine tool after counterweight optimization is compared with that before counterweight optimization. Furthermore, the dynamic isotropy of the machine tool with fluid counterweight is investigated and compared with that of the machine tool with counterweight block.

Dynamic analysis of a flexure-based compliant stage

Yunsong Du,Tie-Min Li,Guohua Gao 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.11

This paper presents the dynamic analysis of a flexure-based compliant stage. The dynamic model is first obtained, after which the equivalent masses of the flexure hinge, including the axial equivalent mass, the bending equivalent mass, and the shear equivalent mass, are derived. According to this method, the equivalent mass components of the proposed stage are derived by accumulating those of the output platform, input platform, and flexure hinges. Finally, to verify the validity of the proposed method, the first two resonant frequencies and the corresponding mode shapes are analyzed by using finite element analysis (FEA). An experimental platform is fabricated, and experimental results and FEA values appear to be in accordance with the theoretical calculations. This result demonstrates that the dynamic model and equivalent mass are accurate. The dynamic model provides an effective method for calculating equivalent masses, and dynamic characteristics can be precisely estimated from the corresponding analytical models.

VISCOSITY METHODS OF APPROXIMATION FOR A COMMON SOLUTION OF A FINITE FAMILY OF ACCRETIVE OPERATORS

Chen, Jun-Min,Zhang, Li-Juan,Fan, Tie-Gang The Youngnam Mathematical Society 2011 East Asian mathematical journal Vol.27 No.1

In this paper, we try to extend the viscosity approximation technique to find a particular common zero of a finite family of accretive mappings in a Banach space which is strictly convex reflexive and has a weakly sequentially continuous duality mapping. The explicit viscosity approximation scheme is proposed and its strong convergence to a solution of a variational inequality is proved.

Influence of Kluyveromyces marxianus on proteins, peptides, and amino acids in Lactobacillus-fermented milk

Dong-Dong Zhang,Jing-Lan Liu,Tie-Min Jiang,Lu Li,Guo-Zhen Fang,Yan-Pin Liu,Li-Jun Chen 한국식품과학회 2017 Food Science and Biotechnology Vol.26 No.3

With increasing application of yeast in fermented milk, in order to study the effect of yeast on milk protein during the fermentation process, the effects of the presence of Kluyveromyces marxianus in milk fermented by Streptococcus thermophilus and Lactobacillus bulgaricus were investigated. After fermentation, the amino acid, protein, and peptide contents were analyzed by ultra-performance liquid chromatography, two-dimensional gel electrophoresis, and liquid chromatography–mass spectrometry, respectively. After the addition of K. marxianus for fermentation, 25 protein spots changed significantly. These were mostly caseins and bovine serum proteins, and the content of total free amino acids increased by 16.30%; ten types of bioactive peptides were identified. Furthermore, the number of peptide types in milk fermented by K. marxianus increased significantly compared with milk fermented by Lactobacillus. K. marxianus is considered to promote proteometabolism in milk when added with Lactobacillus, generate flavor compounds, and improve the digestion and absorption character of milk.