Bi-Directional Stiffness for Airfoil Camber Morphing

AIAA Journal ◽  
2018 ◽  
Vol 56 (4) ◽  
pp. 1639-1646 ◽  
Author(s):  
Matthew DiPalma ◽  
Farhan Gandhi
Keyword(s):  
Directional Stiffness

Guiding cell migration in 3D: A collagen matrix with graded directional stiffness

2009 ◽  
Vol 66 (3) ◽  
pp. 121-128 ◽  
Author(s):  
Ektoras Hadjipanayi ◽  
Vivek Mudera ◽  
Robert A. Brown
Keyword(s):  
Cell Migration ◽  
Collagen Matrix ◽  
Directional Stiffness

Design of directional stiffness catheter for enhancing target accessibility

2021 ◽  
Vol 35 (12) ◽  
pp. 5781-5786
Author(s):  
Jajun Ryu ◽  
Jung Hwan Ahn ◽  
Daejhoong Yoon ◽  
Hwa Young Kim
Keyword(s):  
Directional Stiffness

scholarly journals Interactions and Optimizations Analysis between Stiffness and Workspace of 3-UPU Robotic Mechanism

2017 ◽  
Vol 17 (2) ◽  
pp. 83-92 ◽  
Author(s):  
Dan Zhang ◽  
Bin Wei
Keyword(s):  
Differential Evolution ◽  
Pareto Front ◽  
Robotic System ◽  
Objective Functions ◽  
Stroke Patients ◽  
Walking Machine ◽  
The One ◽  
Translational Stiffness ◽  
Directional Stiffness ◽  
Changing Tendency

Abstract The interactions between stiffness and workspace performances are studied. The stiffness in x, y and z directions as well as the workspace of a 3-UPU mechanism are studied and optimized. The stiffness of the robotic system in every single moveable direction is measured and analyzed, and it is observed that in the case where one tries to make the x and y translational stiffness larger, the z directional stiffness will be reduced, i.e. the x and y translational stiffness contradicts with the one in z direction. Subsequently, the objective functions for the summation of the x and y translational stiffness and z directional stiffness are established and they are being optimized simultaneously. However, we later found that these two objectives are not in the same scale; a normalization of the objectives is thus taken into consideration. Meanwhile, the robotic system’s workspace is studied and optimized. Through comparing the stiffness landscape and the workspace volume landscape, it is also observed that the z translational stiffness shows the same changing tendency with the workspace volume’s changing tendency while the x and y translational stiffness shows the opposite changing tendency compared to the workspace volume’s. Via employing the Pareto front theory and differential evolution, the summation of the x and y translational stiffness and the volume of the workspace are being simultaneously optimized. Finally, the mechanism is employed to synthesize an exercise-walking machine for stroke patients.

A multi-fiber approach with directional stiffness matrix in reinforced concrete structures

2020 ◽  
Vol 37 (7) ◽  
pp. 2411-2437
Author(s):  
Behrooz Yousefi ◽  
Mohammad Reza Esfahani ◽  
Mohammadreza Tavakkolizadeh
Keyword(s):  
Reinforced Concrete ◽  
Stiffness Matrix ◽  
Finite Strain ◽  
Large Displacement ◽  
Beam Model ◽  
Suggested Approach ◽  
Content Type ◽  
Bond Slip ◽  
Steel Bars ◽  
Directional Stiffness

Purpose This paper aims to develop a new multi-fiber element for predicting the structural behavior of planar-reinforced concrete (RC) members. Design/methodology/approach In this work, an exact multi-directional stiffness matrix is analytically derived based on the post-cracking bond-slip interaction between concrete and steel bars. The approach is also extended for large displacement analysis using Green–Lagrange finite strain tensor. In the proposed formulation, the weak form of governed differential equations is approximated by a trial-function expansion based on a finite strain-description and an additional degree of freedom for steel bars. Findings The findings provide a realistic description of cracking in the concrete structure. Numerical studies are conducted to examine the accuracy of the suggested approach and its capability to predict fairly complex responses of RC models. The findings prove that the proposed element can evaluate local and global responses of RC members, and it can be used as a reliable tool to reflect bond-slip effects in large displacement level. This leads to a robust and precise model for non-linear analysis of RC structures. Originality/value The methodology is capable of simulating coupled inelastic shear-flexural behavior of RC members through local stress field theory and Timoshenko beam model.

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