A one-stage, high-load capacity separation actuator using anti-friction rollers and redundant shape memory alloy wires

2015 ◽  
Vol 86 (12) ◽  
pp. 125005 ◽  
Author(s):  
Yan Xiaojun ◽  
Huang Dawei ◽  
Zhang Xiaoyong ◽  
Liu Ying ◽  
Yang Qiaolong
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Load Capacity ◽  
High Load ◽  
One Stage ◽  
High Load Capacity

The cyclic response of circular reinforced concrete column to foundation connections strengthened with shape memory alloy bars

2020 ◽  
pp. 002199832096144
Author(s):  
Mahdieh Miralami ◽  
M Reza Esfahani ◽  
Mohammadreza Tavakkolizadeh ◽  
Reza Khorramabadi ◽  
Jalil Rezaeepazhand
Keyword(s):  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Load Capacity ◽  
Lateral Load ◽  
Reference Specimen ◽  
Initial Stiffness ◽  
Residual Displacement ◽  
Cfrp Sheets ◽  
Column Foundation

This study presents a new method for strengthening the circular reinforced concrete (RC) column to foundation connections with shape memory alloy (SMA) bars and carbon fiber reinforced polymer (CFRP) sheets. In the experimental part of the study, three specimens of RC column-foundation connections were cast and tested. One specimen was used as the reference specimen without strengthening. Two other specimens were strengthened with longitudinal SMA bars and CFRP sheets. These specimens were under a constant axial compressive load and cyclic lateral displacements, simultaneously. Next, initial stiffness, energy dissipation capacity, lateral load capacity, ductility, and residual displacement of the specimens were investigated. Due to the superelastic behavior of SMA bars, the residual displacement of column-foundation connections was considerably less than that of the reference specimen. Compared to the reference specimen, the SMA-strengthened and SMA-CFRP-strengthened connections recovered 71.59% and 76.57% of the residual displacement. Therefore, SMA bars were able to recover residual displacements under cyclic loading. Also, the combination of the SMA bars with CFRP sheet was a promising solution for enhancing the amount of the energy dissipation, lateral load capacity, initial stiffness, and ductility parameters. Compared to the reference specimen, the energy dissipation, lateral load capacity, initial stiffness, and ductility ratio parameters of SMA-CFRP-strengthened connection increased about 43.45%, 76.20%, 81.69%, and 242.45%, respectively. In the numerical part of the study, a subroutine was applied for modeling the SMA materials. For the analysis, this subroutine was linked with ABAQUS software. The numerical results showed a close correlation with the experimental results.

An Air Layer Modeling Approach for Air and Air/Vacuum Bearings

1997 ◽  
Vol 119 (3) ◽  
pp. 388-392
Author(s):  
J. M. Pitarresi ◽  
K. A. Haller
Keyword(s):  
Load Capacity ◽  
Load Resistance ◽  
High Load ◽  
Air Bearing ◽  
Air Bearings ◽  
Bearing Surface ◽  
Know How ◽  
Modeling Approach ◽  
Vibrational Characteristics ◽  
High Load Capacity

Air layer supported bearing pads, or “air bearings” as they are commonly called, are popular because of their high load capacity and low in-plane coefficient of friction, making them well suited for supporting moving, high accuracy manufacturing stages. Air/vacuum bearings enhance these capabilities by giving the bearing pad load resistance capacity in both the upward and downward directions. Consequently, it is desirable to know how to model the air layer between the bearing pad and the bearing surface. In this paper, a simple finite element modeling approach is presented for investigating the vibrational characteristics of an air layer supported bearing. It was found that by modeling the air layer as a bed of uniform springs who’s stiffness is determined by load-displacement tests of the bearing, a reasonable representation of the response can be obtained. For a bearing supported by air without vacuum, the dynamic response was very similar to that of a freely supported bearing. The addition of vacuum to an air bearing was found to significantly lower its fundamental frequency which could lead to unwanted resonance problems.

Characteristics of Experimental MSMA-Based Pneumatic Valves

2013 ◽  
Author(s):  
Stanislaw Flaga ◽  
Andrzej Sioma
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Initial Study ◽  
General Construction ◽  
Linear Actuator ◽  
Magnetic Shape Memory ◽  
Electromechanical Transducer ◽  
One Stage ◽  
Magnetic Shape Memory Alloy ◽  
Pneumatic Valves

In the course of work on a linear actuator based on a magnetic shape memory alloy (MSMA), a research workstation was constructed enabling the examination of pneumatic valves featuring an electromechanical transducer created with MSMA technology. In this article, the general construction of the research workstation is presented, together with an initial study of a demonstrator of a pneumatic, one-stage, one-way throttle valve. In the presented demonstrator, a simple replacement of a electromechanical transducer into a transducer created with MSMA technology was performed. In addition, the study also describes the problems appearing in such structures along with potential troubleshooting methods.

scholarly journals Analysis of the geometry and contact density of globoid gearing

2020 ◽  
Vol 329 ◽  
pp. 03008
Author(s):  
Aleksandr Vyatkin
Keyword(s):  
Numerical Methods ◽  
Load Capacity ◽  
High Load ◽  
Design Stage ◽  
Energy Losses ◽  
Technological Parameters ◽  
Contact Density ◽  
Small Energy ◽  
Worm Gears ◽  
High Load Capacity

Globoid worm gears have been widely applied in a range of technological branches in which other types of worm gears are less effective. The main functional indicators which facilitated their popularity include high load capacity and durability, low vibroactivity and small energy losses. As the experience of application and the results of the study of globoid worm gears showed, the level of operational properties of globoid gears is higher than that of the others only if the gearing and technological parameters of their manufacturing are optimally chosen during the design stage. This paper describes a method for estimating the gearing parameters of a globoid gear with an account of the geometry of the elements (the geometry of the teeth of the wheel and the worm thread), namely the calculation of the gap fields in the globoid gearing by means of numerical methods.

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