scholarly journals Lateral Response Comparison of Unbonded Elastomeric Bearings Reinforced with Carbon Fiber Mesh and Steel

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Ali Karimzadeh Naghshineh ◽  
Ugurhan Akyuz ◽  
Alp Caner
Keyword(s):  
Classical Equation ◽  
Experimental Tests ◽  
Elastic Behavior ◽  
Fiber Reinforced ◽  
Elastomeric Bearings ◽  
Cyclic Shear ◽  
Vertical Stiffness ◽  
Elastomeric Material ◽  
Lateral Response ◽  
Fiber Mesh

The vertical and horizontal stiffness used in design of bearings have been established in the last few decades. At the meantime, applicability of the theoretical approach developed to estimate vertical stiffness of the fiber-reinforced bearings has been verified in different academic studies. The suitability of conventional horizontal stiffness equation developed for elastomeric material, mainly for steel-reinforced elastomeric bearings, has not been tested in detail for use of fiber-reinforced elastomeric bearings. In this research, lateral response of fiber mesh-reinforced elastomeric bearings has been determined through experimental tests and the results have been compared by corresponding values pertaining to the steel-reinforced bearings. Within the test program, eight pairs of fiber mesh-reinforced bearings and eight pairs of steel-reinforced bearings are subjected to different levels of compressive stress and cyclic shear strains. Fiber-reinforced elastomeric bearings may be more favorable to be used in seismic regions due to lower horizontal stiffness that can result in mitigation of seismic forces for levels of 100% shear strain. Damping properties of these types of fiber mesh-reinforced bearings depend mostly on the selection of elastomeric material compounds. Suggestions have been made for the lateral response of fiber-reinforced elastomeric bearings. It has also been determined that the classical equation for lateral stiffness based on linear elastic behavior assumptions developed for elastomeric bearings does not always apply to the fiber-reinforced ones.

Fiber-Reinforced Elastomeric Bearings for Vibration Isolation

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
James M. Kelly ◽  
Niel C. Van Engelen
Keyword(s):  
Seismic Isolation ◽  
Vibration Isolation ◽  
Fiber Reinforcement ◽  
Compression Modulus ◽  
Additional Parameter ◽  
Fiber Reinforced ◽  
Elastomeric Bearings ◽  
Vertical Stiffness ◽  
Elastomeric Bearing ◽  
Fiber Materials

Fiber-reinforced elastomeric bearings were originally proposed as an alternative to conventional steel-reinforced elastomeric bearings for seismic isolation applications. The flexible fiber reinforcement is a light-weight and potentially cost saving alternative to steel reinforcement which is assumed rigid in the design process. The variety of fiber materials available also serves as an additional parameter for designers to tailor the vertical stiffness of the bearing. In this paper, the analytical solution for the vertical compression modulus of a rectangular elastomeric pad including the effects of bulk compressibility and extensibility of the fiber reinforcement is used to investigate the achievable decrease in vertical frequency. It is shown by an example that the extensibility of the fiber reinforcement can be used to significantly reduce the vertical stiffness in comparison to an equivalent steel-reinforced elastomeric bearing. The resulting decrease in the vertical frequency means that fiber-reinforced elastomeric bearings may have an advantage over steel-reinforced bearings in the vibration isolation of buildings.

On axial compressive behavior of steel fiber reinforced concrete confined by FRP

2021 ◽  
pp. 136943322098165
Author(s):  
Hossein Saberi ◽  
Farzad Hatami ◽  
Alireza Rahai
Keyword(s):  
Reinforced Concrete ◽  
Experimental Test ◽  
Steel Fiber ◽  
Experimental Tests ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Test Results ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Frp Confinement

In this study, the co-effects of steel fibers and FRP confinement on the concrete behavior under the axial compression load are investigated. Thus, the experimental tests were conducted on 18 steel fiber-reinforced concrete (SFRC) specimens confined by FRP. Moreover, 24 existing experimental test results of FRP-confined specimens tested under axial compression are gathered to compile a reliable database for developing a mathematical model. In the conducted experimental tests, the concrete strength was varied as 26 MPa and 32.5 MPa and the steel fiber content was varied as 0.0%, 1.5%, and 3%. The specimens were confined with one and two layers of glass fiber reinforced polymer (GFRP) sheet. The experimental test results show that simultaneously using the steel fibers and FRP confinement in concrete not only significantly increases the peak strength and ultimate strain of concrete but also solves the issue of sudden failure in the FRP-confined concrete. The simulations confirm that the results of the proposed model are in good agreement with those of experimental tests.

scholarly journals Finite Element Analysis for Nonlinear Unbonded Circular Fiber-Reinforced Elastomeric Bearings

2021 ◽  
Vol 5 (7) ◽  
pp. 170
Author(s):  
Pablo Castillo Ruano ◽  
Alfred Strauss
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Carbon Fiber ◽  
Seismic Isolation ◽  
Nonlinear Viscoelasticity ◽  
Fiber Reinforcement ◽  
Special Focus ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Elastomeric Bearings

In recent years, interest in low-cost seismic isolation systems has increased. The replacement of the steel reinforcement in conventional elastomeric bearings for a carbon fiber reinforcement is a possible solution and has garnered increasing attention. To investigate the response of fiber-reinforced elastomeric bearings (FREBs) under seismic loads, it is fundamental to understand its mechanical behavior under combined vertical and horizontal loads. An experimental investigation of the components presents complexities due to the high loads and displacements tested. The use of a finite element analysis can save time and resources by avoiding partially expensive experimental campaigns and by extending the number of geometries and topologies to be analyzed. In this work, a numerical model for carbon fiber-reinforced bearings is implemented, calibrated, and validated and a set of virtual experiments is designed to investigate the behavior of the bearings under combined compressive and lateral loading. Special focus is paid to detailed modeling of the constituent materials. The elastomeric matrix is modeled using a phenomenological rheological model based on the hyperelastic formulation developed by Yeoh and nonlinear viscoelasticity. The model aims to account for the hysteretic nonlinear hyper-viscoelastic behavior using a rheological formulation that takes into consideration hyperelasticity and nonlinear viscoelasticity and is calibrated using a series of experiments, including uniaxial tension tests, planar tests, and relaxation tests. Special interest is paid to capturing the energy dissipated in the unbonded fiber-reinforced elastomeric bearing in an accurate manner. The agreement between the numerical results and the experimental data is assessed, and the influence of parameters such as shape factor, aspect ratio, vertical pressure, and fiber reinforcement orientation on stress distribution in the bearings as well as in the mechanical properties is discussed.

Numerical Analysis on the Structural Behavior of a Non-Engaging CFRP Bellows Coupling for Propulsion Technology

2017 ◽  
Vol 742 ◽  
pp. 723-731 ◽  
Author(s):  
Christian Oblinger ◽  
André Baeten ◽  
Klaus Drechsler
Keyword(s):  
Numerical Analysis ◽  
Torsional Stiffness ◽  
Fiber Reinforced Polymers ◽  
Structural Behavior ◽  
Elastic Behavior ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Geometrical Design ◽  
Energy Applications ◽  
Design Variables

Fiber reinforced polymers (FRP) are used in a widespread range, for example in aerospace, mobility or wind energy applications due to their excellent quality profile. Moreover, rotating machine elements, which are applied in dynamic processes, require a primarily high stiffness combined with an elastic behavior. Novel FRP components or modern hybrid structures lead to a lower energy consumption of the entire mechanical system. In this respect, a shaft coupling between two shafts depicts an exemplary machine element for a possible application of FRP. This paper deals with the numerical analysis on the structural behavior of a non-engaging bellows coupling made of prepreg-based carbon fiber reinforced polymers (CFRP) for propulsion technology. The presented concept is based on the methodological construction approach for the fulfillment of the compensation and connection functionality. A very high torsional stiffness as well as a certain bending flexibility of the whole coupling geometry is required due to the connection of two torsion-loaded structures. Specific geometrical design variables could be identified with the finite elements method (FEM) and the design of experiments (DoE), which have a significant influence on the structure mechanical behavior of the CFRP bellows coupling. Based on a variable identification scheme according to Shainin, the influence of various geometrical design factors on the structural performance of the CFRP bellows coupling was evaluated.

scholarly journals Stiffness Analysis of Rectangular Isolators Reinforced by Engineering Plastics

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Han Liu ◽  
Ping Tan ◽  
Fulin Zhou
Keyword(s):  
Finite Element Analysis ◽  
Experimental Tests ◽  
Cost Effective ◽  
Seismic Protection ◽  
Fiber Reinforced ◽  
Poisson Effect ◽  
Element Analysis ◽  
Stiffness Analysis ◽  
Engineering Plastics ◽  
Improve Calculation

A novel cost-effective isolator reinforced by engineering plastics has been designed and manufactured for seismic protection for low-rise buildings in less developed areas. The reinforcement is flexible in tension, which is similar to fiber-reinforced isolators. However, available solutions for fiber-reinforced isolators are not applicable, because the Poisson effect of engineering plastics cannot be neglected, which is done for fiber reinforcement. In this paper, analytical solutions for compression and bending stiffness for rectangular isolators reinforced by engineering plastics are proposed, with both the Poisson effect of the reinforcement and the effect of rubber compressibility taken into consideration. Then, the simplified solutions are also derived, which can greatly improve calculation efficiency. To validate the solutions, finite element analysis is conducted on a set of isolators with different reinforcement stiffnesses. The results show the superiority of the proposed solutions to the previous solutions for fiber-reinforced isolators. A series of experimental tests of the isolators are also carried out to verify the solutions. Both the analytical and the simplified solutions match well with the experimental results.

Experimental and finite element study on the lateral response of modified rectangular fiber-reinforced elastomeric isolators (MR-FREIs)

2015 ◽  
Vol 85 ◽  
pp. 293-303 ◽  
Author(s):  
Peyman M. Osgooei ◽  
Niel C. Van Engelen ◽  
Dimitrios Konstantinidis ◽  
Michael J. Tait
Keyword(s):  
Finite Element ◽  
Fiber Reinforced ◽  
Finite Element Study ◽  
Lateral Response ◽  
Element Study
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