Fiber-Reinforced Membrane Models of McKibben Actuators

2003 ◽  
Vol 70 (6) ◽  
pp. 853-859 ◽  
Author(s):  
W. Liu ◽  
C. R. Rahn
Keyword(s):  
Axial Load ◽  
Cylindrical Tube ◽  
Longitudinal Axis ◽  
Fiber Reinforced ◽  
Initial Shape ◽  
Fiber Angle ◽  
Inner Pressure ◽  
Membrane Models ◽  
Mckibben Actuators ◽  
Inextensible Fibers

A McKibben actuator consists of an internally pressurized elastic cylindrical tube covered by a shell braided with two families of inextensible fibers woven at equal and opposite angles to the longitudinal axis. Increasing internal pressure causes the actuator to expand radially and, due to the fiber constraint, contract longitudinally. This contraction provides a large force that can be used for robotic actuation. Based on large deformation membrane theory, the actuator is modeled as a fiber-reinforced cylinder with applied inner pressure and axial load. Given the initial shape, material parameters, axial load, and pressure, the analytical model predicts the deformed actuator shape, fiber angle, and fiber and membrane stresses. The analytical results show that for a long and thin actuator the deformed fiber angle approaches 54°44′ at infinite pressure. The actuator elongates and contracts for actuators with initial angles above and below 54°44′ degrees, respectively. For short and thick actuators with initial angles relatively close to 0 deg or 90 deg, however, a fiber angle boundary layer extends to the middle of the actuator, limiting possible extension or contraction. The calculated longitudinal strain and radius change match experimental results to within 5%.

Study the Behavior of Castellated Steel Column Encasing by Different Reactive Powder Concrete Thickness with Laced Reinforcement

2021 ◽  
Vol 895 ◽  
pp. 97-109
Author(s):  
Mustafa Mazin Ghazi ◽  
Ahmad Jabbar Hussain Alshimmeri
Keyword(s):  
Axial Load ◽  
Local Buckling ◽  
Axial Loading ◽  
Longitudinal Axis ◽  
Load Test ◽  
Reactive Powder Concrete ◽  
Control Group ◽  
Load Carrying ◽  
Steel Column ◽  
Reactive Powder

Castellated columns are structural members that are created by breaking a rolled column along the center-line by flame after that rejoining the equivalent halves by welding such that for better structural strength against axial loading, the total column depth is increased by around 50 percent. The implementation of these institutional members will also contribute to significant economies of material value. The main objectives of this study are to study the enhancement of the load-carrying capacity of castellated columns with encasement of the columns by Reactive Powder Concrete (RPC) and lacing reinforcement, and serviceability of the confined castellated columns. The Castellated columns with RPC and Lacing Reinforcement improve compactness and local buckling (web and flange local buckling), as a result of steel section encasement. This study presents axial load test results for four specimens Castellated columns section encasement by Reactive powder concrete (RPC) with laced reinforcement. The encasement consists of, flanges unstiffened element height was filled with RPC for each side and laced reinforced which are used inclined continuous reinforcement of two layers on each side o0f the web of the castellated column. The inclination angle of lacing reinforcement concerning the longitudinal axis is 45o. Four specimens with four different configurations will be prepared and tested under axial load at columns. The first group was the control group (CSC1) Unconfined castellated steel column, the second group was consists of Castellated columns (web and flange) confined with 17mm of (RPC), welded web, and 6mm laced reinforcement (CSC3). While group three (CSC4) consists of a Castellated steel column same as the sample (CSC3), but without using welding between two parts of the castellated steel column. Groups four and five consist of a Castellated steel column same as sample (CSC4) encased partially with reactive powder concrete (25.5 mm) (CSC5) and full encased flange with reactive powder concrete (34mm) mm (CSC6), respectively. The tested specimens' results show that an increase in the strength of the column competitive with increasing the encased reactive powder concrete thickness. And the best sample was sample CSC6 with (34mm) mm in experimental and ABAQUS results.

scholarly journals Deformation characteristic of the axially fiber reinforced cylindrical rubber subjected to inner pressure

2018 ◽  
Vol 84 (868) ◽  
pp. 18-00351-18-00351
Author(s):  
Tomoaki TSUJI ◽  
Akihiro KOJIMA ◽  
Manabu OKUI ◽  
Itsuki HISAMICHI ◽  
Taro NAKAMURA
Keyword(s):  
Deformation Characteristic ◽  
Fiber Reinforced ◽  
Inner Pressure

Numerical Analyses of Axial Load Effect on Shear Strength of Concrete and Gypsum Composite Walls

2013 ◽  
Vol 353-356 ◽  
pp. 3623-3629
Author(s):  
Kang Liu
Keyword(s):  
Shear Strength ◽  
Glass Fiber ◽  
Axial Load ◽  
Numerical Analyses ◽  
Green Product ◽  
Fiber Reinforced ◽  
Load Effect ◽  
Glass Fiber Reinforced ◽  
Save Energy ◽  
Composite Walls

Gypsum walls are a green product that helps to save energy and protect the environment. This paper numerically investigates the effect of axial load on shear strength of glass fiber reinforced gypsum (GFRG) walls fully or partially filled with concrete in the hollow cores. The conclusion drawn in this paper is general and applicable to other kinds of walls.

The Effect of Bending on the Normalized Stress at Roots of Threaded Connectors

1994 ◽  
Vol 116 (3) ◽  
pp. 163-166 ◽  
Author(s):  
R. L. Burguete ◽  
E. A. Patterson
Keyword(s):  
Axial Load ◽  
Stress Ratio ◽  
Axial Stress ◽  
Three Dimensional ◽  
Longitudinal Axis ◽  
Nominal Stress ◽  
Bending Stress ◽  
Fringe Order ◽  
Bending Load ◽  
Thin Slices

Three-dimensional photoelasticity was used to analyze the effect of bending on the normalized stress at the roots of threaded connectors. Loading was effected by steel cages and a combination of eccentric weights (to provide the bending load) and concentric weights (to provide the axial load). The ratio of the bending stress to the axial stress was determined and various levels of this stress ratio, Rσ, were tested. The connections were analyzed by taking thin slices in the plane of bending and perpendicular to it. The position of the maximum fringe order at the roots was determined using Mesnager’s theorem and the maximum fringe order found by Tardy compensation. The fringe orders were normalized using the nominal axial stress and the total nominal stress (bending plus axial stress), which were calculated from the loads applied. The results, when normalized using the nominal axial stress and compared to those in connections without bending, exhibit a lower and broader peak of normalized stress values plotted against the helix length. The normalized stress values are also periodic in relation to the bending plane due to the variation in stress around the longitudinal axis of the bolt. It was found that bending in connectors will affect the normalized stress and that it is possible to determine this effect in a similar way to the method used for axially loaded connections.

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