Nonlinear membrane stiffness model of a tennis racquet string bed

2017 ◽  
Vol 232 (1) ◽  
pp. 57-65
Author(s):  
Huihui Hong ◽  
Liang Han ◽  
NC Perkins ◽  
Chuan Hu ◽  
JR Barber
Keyword(s):  
Stiffness Model ◽  
Membrane Stiffness ◽  
Nonlinear Membrane

Lectin-Induced RBC Agglutination: Chemical vs. Cryofixation

1980 ◽  
Vol 38 ◽  
pp. 664-665
Author(s):  
Dean A. Handley ◽  
Lanping A. Sung ◽  
Shu Chien
Keyword(s):  
Lectin Binding ◽  
Freeze Substitution ◽  
Electrostatic Charge ◽  
Geometric Parameters ◽  
Comparative Approach ◽  
Chemical Fixation ◽  
Cell Surfaces ◽  
Minimal Cell ◽  
Membrane Stiffness ◽  
Cell Contour

RBC agglutination by lectins represents an interactive balance between the attractive (bridging) force due to lectin binding on cell surfaces and disaggregating forces, such as membrane stiffness and electrostatic charge repulsion (1). During agglutination, critical geometric parameters of cell contour and intercellular distance reflect the magnitude of these interactive forces and the size of the bridging macromolecule (2). Valid ultrastructural measurements of these geometric parameters from agglutinated RBC's require preservation with minimal cell distortion. As chemical fixation may adversely influence RBC geometric properties (3), we used chemical fixation and cryofixation (rapid freezing followed by freeze-substitution) as a comparative approach to examine these parameters from RBC agglutinated with Ulex I lectin.

A realistic model for transverse shear stiffness prediction of composite corrugated-core sandwich structure with bonding effect

2021 ◽  
pp. 109963622199386
Author(s):  
Tianshu Wang ◽  
Licheng Guo
Keyword(s):  
Present Model ◽  
Shear Stiffness ◽  
Realistic Model ◽  
Torsional Stiffness ◽  
Fem Model ◽  
The Core ◽  
Bonding Effect ◽  
Stiffness Model ◽  
Bonding Area ◽  
The Relationship

In this paper, a shear stiffness model for corrugated-core sandwich structures is proposed. The bonding area is discussed independently. The core is thought to be hinged on the skins with torsional stiffness. The analytical model was verified by FEM solution. Compared with the previous studies, the new model can predict the valley point of the shear stiffness at which the relationship between the shear stiffness and the angle of the core changes from negative correlation to positive correlation. The valley point increases when the core becomes stronger. For the structure with a angle of the core smaller than counterpart for the valley point, the existing analytical formulations may significantly underestimate the shear stiffness of the structure with strong skins. The results obtained by some previous models may be only 10 persent of that of the present model, which is supported by the FEM model.

Stiffness Constants for Composite Beams Including Large Initial Twist and Curvature Effects

1995 ◽  
Vol 48 (11S) ◽  
pp. S61-S67 ◽  
Author(s):  
Carlos E. S. Cesnik ◽  
Dewey H. Hodges
Keyword(s):  
Wave Length ◽  
Three Dimensional ◽  
Radius Of Curvature ◽  
Cross Sectional ◽  
Curvature Effects ◽  
Three Dimensional Representation ◽  
Stiffness Model ◽  
Sectional Analysis ◽  
Three Dimensional Elasticity ◽  
Coupling Phenomena

An asymptotically exact methodology, based on geometrically nonlinear, three-dimensional elasticity, is presented for cross-sectional analysis of initially curved and twisted, nonhomogeneous, anisotropic beams. Through accounting for all possible deformation in the three-dimensional representation, the analysis correctly accounts for the complex elastic coupling phenomena in anisotropic beams associated with shear deformation. The analysis is subject only to the restrictions that the strain is small relative to unity and that the maximum dimension of the cross section is small relative to the wave length of the deformation and to the minimum radius of curvature and/or twist. The resulting cross-sectional elastic constants exhibit second-order dependence on the initial curvature and twist. As is well known, the associated geometrically-exact, one-dimensional equilibrium and kinematical equations also depend on initial twist and curvature. The corrections to the stiffness model derived herein are also necessary in general for proper representation of initially curved and twisted beams.

Dynamic analysis for a spur geared rotor system with tooth tip chipping based on an improved time-varying mesh stiffness model

2021 ◽  
Vol 165 ◽  
pp. 104435
Author(s):  
Yi Yang ◽  
Niaoqing Hu ◽  
Jinyuan Tang ◽  
Jiao Hu ◽  
Lun Zhang ◽  
...  
Keyword(s):  
Dynamic Analysis ◽  
Rotor System ◽  
Time Varying ◽  
Mesh Stiffness ◽  
Stiffness Model

An Improved Stiffness Model for Bolted Joints

2009 ◽  
Vol 131 (12) ◽  
Author(s):  
Sayed A. Nassar ◽  
Antoine Abboud
Keyword(s):  
Joint Stiffness ◽  
Effective Area ◽  
Accurate Estimate ◽  
Diameter Ratio ◽  
Bolted Joints ◽  
Plate Material ◽  
Reliable Prediction ◽  
Novel Approach ◽  
Stiffness Model ◽  
Initial Assembly

An improved stiffness model is proposed for bolted joints made of similar and dissimilar plates. A novel approach is used to obtain an expression for the effective area used for determining the joint stiffness. More accurate estimate of the joint stiffness provides a more reliable prediction of the joint behavior both during its initial assembly, as well as under subsequently applied tensile loads in service. The effect of the grip length-to-diameter ratio, joint sizes, underhead contact radii ratio, hole clearance, and plate material/thickness ratio are investigated. Experimental data are used for determining the envelope angle α in the proposed analytical model. Finite element modeling is used for evaluating the accuracy of the proposed stiffness model.

scholarly journals Conceptual design and comparative stiffness analysis of an Exechon-like parallel kinematic machine with lockable spherical joints

2017 ◽  
Vol 14 (4) ◽  
pp. 172988141772413
Author(s):  
Teng-fei Tang ◽  
Jun Zhang
Keyword(s):  
Conceptual Design ◽  
Prediction Accuracy ◽  
Parallel Kinematic Machine ◽  
Stiffness Analysis ◽  
Parallel Kinematic Machines ◽  
Stiffness Model ◽  
Dynamic Analyses ◽  
Parallel Kinematic ◽  
Kinetostatic Model ◽  
Limb Structure

This article proposes two types of lockable spherical joints which can perform three different motion patters by locking or unlocking corresponding rotational axes. Based on the proposed lockable spherical joints, a general reconfigurable limb structure with two passive joints is designed with which the conceptual designs of two types of Exechon-like parallel kinematic machines are completed. To evaluate the stiffness of the proposed Exechon-like parallel kinematic machines, an expanded kinetostatic model is established by including the compliances of all joints and limb structures. The prediction accuracy of the expanded stiffness model is validated by numerical simulations. The comparative stiffness analyses prove that the Exe-Variant parallel kinematic machine claims competitive rigidity performance to the Exechon parallel kinematic machine. The present work can provide useful information for further investigations on structural enhancement, rigidity improvement, and dynamic analyses of other Exechon-like parallel kinematic machines.

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