scholarly journals Analysis of RC Deep Beams Considering the Shear Deformations and Bar-concrete Interaction

Author(s):  
Seyed Shaker Hashemi ◽  
Kabir Sadeghi ◽  
Saeid Javidi ◽  
Mahmoud Malakouti

In this paper, reinforced concrete (RC) deep beams (DBs) have been analyzed numerically and a new approach is proposed to the nonlinear numerical modeling of such structural members. The effect of shear deformations and the interaction between reinforcing steel bar and concrete are considered in modeling and analysis. In order to consider the effect of shear deformations, the Timoshenko beam theory has been applied to formulate the analysis method. In the modeling, the RC DB is divided into several sub-elements which are composed of concrete and reinforcing steel bars. Individual degrees of freedom have been assigned to each reinforcing steel bar. Thus, each reinforcing steel bar is able to slip relative to its surrounding concrete and the bond effect is simulated by nonlinear springs. To consider the interaction between reinforcing steel bar and concrete, the concrete segment acts as a beam element, and each reinforcing steel bar acts as a truss element. The reliability of this method has been confirmed by comparing the obtained results from the numerical analysis and the results of the experimental pushover test.

Structures ◽  
2021 ◽  
Vol 31 ◽  
pp. 1106-1129
Author(s):  
Mona K. Ghali ◽  
Mohamed Said ◽  
T.S. Mustafa ◽  
Abdallah A. El-Sayed

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1468
Author(s):  
Luis Nagua ◽  
Carlos Relaño ◽  
Concepción A. Monje ◽  
Carlos Balaguer

A soft joint has been designed and modeled to perform as a robotic joint with 2 Degrees of Freedom (DOF) (inclination and orientation). The joint actuation is based on a Cable-Driven Parallel Mechanism (CDPM). To study its performance in more detail, a test platform has been developed using components that can be manufactured in a 3D printer using a flexible polymer. The mathematical model of the kinematics of the soft joint is developed, which includes a blocking mechanism and the morphology workspace. The model is validated using Finite Element Analysis (FEA) (CAD software). Experimental tests are performed to validate the inverse kinematic model and to show the potential use of the prototype in robotic platforms such as manipulators and humanoid robots.


2020 ◽  
Vol 21 (3) ◽  
pp. 917-933
Author(s):  
Xi Liu ◽  
Tao Wu ◽  
Yuanyuan An ◽  
Yang Liu

2017 ◽  
Vol 23 (10) ◽  
pp. 1377-1388 ◽  
Author(s):  
Seyyed Abbas Mohammadi ◽  
Heinrich Voss

This paper proposes a new approach for computing the real eigenvalues of a multiple-degrees-of-freedom viscoelastic system in which we assume an exponentially decaying damping. The free-motion equations lead to a nonlinear eigenvalue problem. If the system matrices are symmetric, the eigenvalues allow for a variational characterization of maxmin type, and the eigenvalues and eigenvectors can be determined very efficiently by the safeguarded iteration, which converges quadratically and, for extreme eigenvalues, monotonically. Numerical methods demonstrate the performance and the reliability of the approach. The method succeeds where some current approaches, with restrictive physical assumptions, fail.


2014 ◽  
Vol 11 (3) ◽  
pp. 229-232
Author(s):  
Rahul Hingole ◽  
Vilas Nandedkar

The term springback is defined as the change in geometry of a component after forming, when the forces are removed from forming tools. As springback affects the final shape of the part, it can lead to significant difficulties in the assembly of component when springback is not proper. This problem leads to fabrication of inconsistent sheet metal parts; the elastic strain recovery in the material after the tooling is removed. Bendingis the plastic deformation of metals about a linear axis called the bending axis with little or no change in the surface area. Bending types of forming operations have been used widely in sheet metal forming industries to produce structural stamping parts such as braces, brackets, supports, hinges, angles, frames, channel and other nonsymmetrical sheet metal parts. Among them, quite a few efforts have been made to obtain a deep understanding of the springback phenomenon. The beam theory has been applied to formulate the curvature before and after loading of pipe. This research work has focused on study effect of springback effect with a new approach. The ANSYS software is used to analyze spring back effect. The detail study of this springback effect is presented in this paper.


Fibers ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 52 ◽  
Author(s):  
Constantin Chalioris ◽  
Parthena-Maria Kosmidou ◽  
Nikos Papadopoulos

The effectiveness of a new retrofitting technique to upgrade the structural behaviour of reinforced concrete (RC) deep beams without steel stirrups using carbon fibre-reinforced polymer (CFRP) ropes as the only transverse shear reinforcement is experimentally investigated. Five shear-critical beams with rectangular and T-shaped cross-section are tested under monotonic loading. The strengthening schemes include (a) one vertical and one diagonal single-link CFRP rope that are internally applied through the web of the rectangular beam using an embedded through-section (ETS) system and (b) two vertical U-shaped double-link ropes that are applied around the perimeter of the web of the flanged beam using a near-surface-mounted (NSM) system. In both cases, the free lengths of the CFRP ropes have been properly anchored using epoxy bonded lap splices of the rope as NSM at (a) the top and the bottom of the web of the rectangular beam and (b) the top of the slab of the T-beam. Promising results have been derived, since the proposed strengthening technique enhanced the strength and altered the brittle shear failure to a ductile flexural one. The experimental results of this study were also used to check the validity of an analytical approach to predict the strength of shear strengthened deep beams using FRP ropes as transverse link reinforcement.


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