Optimal free length of bender and extender elements used for seismic testing in geotechnical centrifuges

2013 ◽  
pp. 317-323
Author(s):  
A Archer ◽  
G Heymann
Keyword(s):  
Free Length ◽  
Seismic Testing ◽  
Geotechnical Centrifuges

scholarly journals Compressive Strength of Modified FRP Hybrid Bars

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1898
Author(s):  
Marek Urbański
Keyword(s):  
Compressive Strength ◽  
Modulus Of Elasticity ◽  
Basalt Fiber ◽  
Test Method ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Free Length ◽  
Compression Properties ◽  
Reinforced Polymer ◽  
Frp Bars

A new type of HFRP hybrid bars (hybrid fiber reinforced polymer) was introduced to increase the rigidity of FRP reinforcement, which was a basic drawback of the FRP bars used so far. Compared to the BFRP (basalt fiber reinforced polymer) bars, modification has been introduced in HFRP bars consisting of swapping basalt fibers with carbon fibers. One of the most important mechanical properties of FRP bars is compressive strength, which determines the scope of reinforcement in compressed reinforced concrete elements (e.g., column). The compression properties of FRP bars are currently ignored in the standards (ACI, CSA). The article presents compression properties for HFRP bars based on the developed compression test method. Thirty HFRP bars were tested for comparison with previously tested BFRP bars. All bars had a nominal diameter of 8 mm and their nonanchored (free) length varied from 50 to 220 mm. Test results showed that the ultimate compressive strength of nonbuckled HFRP bars as a result of axial compression is about 46% of the ultimate strength. In addition, the modulus of elasticity under compression does not change significantly compared to the modulus of elasticity under tension. A linear correlation of buckling load strength was proposed depending on the free length of HFRP bars.

Variability Associated with Seismic Testing Methods

1980 ◽  
Author(s):  
R. Vasudevan ◽  
R. Campbell
Keyword(s):  
Testing Methods ◽  
Seismic Testing

Performance of Earthquake Simulation Three Bi-Axial Shaking Tables

2014 ◽  
Vol 518 ◽  
pp. 178-183 ◽  
Author(s):  
Fu Yun Huang ◽  
Zi Ming Fang ◽  
Jian Zhong Li
Keyword(s):  
Earthquake Simulation ◽  
Elastic Structures ◽  
Prospective Development ◽  
Testing Platform ◽  
Seismic Testing ◽  
Perfect Performance ◽  
Development Direction

The shaking tables array is the prospective development direction in engineering structural anti-seismic researching field, and which can provide a powerful seismic testing platform. In this paper, the performance of three bi-axial shaking tables array at Fuzhou University was introduced. The trails of bare tables, fully inertial payload shaking tables as well as partly payload shaking tables with elastic structures were conducted. The testing reveals that the shaking tables array system of Fuzhou University has a perfect performance of compliance, coherence and synchronization, which are accepted the required.

Modular Advantage and Kinematic Decoupling in Gravity Compensated Robotic Systems

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
Nick Eckenstein ◽  
Mark Yim
Keyword(s):  
Vertical Plane ◽  
Robotic Systems ◽  
Gravity Compensation ◽  
Pulley System ◽  
Free Length ◽  
Low Profile ◽  
Serial Chain ◽  
Manipulator Arm ◽  
Spring Method ◽  
Position And Orientation

Two new designs for gravity compensated modular robotic systems are presented and analyzed. The gravity compensation relies on using zero-free-length springs approximated by a cable and pulley system. Simple yet powerful parallel four-bar modules enable the low-profile self-contained modules with sequential gravity compensation using the spring method for motion in a vertical plane. A second module that is formed as a parallel six-bar mechanism adds a horizontal motion to the previous system that also yields a complete decoupling of position and orientation of the distal end of a serial chain. Additionally, we introduce the concept of vanishing effort where as the number of modules that comprise an articulated serial chain increases, the actuation authority required at any joint reduces. Essentially, this results in a method for distributing actuation along the length of an articulated chain. Prototypes were designed and constructed validating the analysis and accomplishing the functions of a general serial-type manipulator arm.

The Damping Study for Dammar Composites Reinforced with Natural Fibers

2015 ◽  
Vol 801 ◽  
pp. 188-193
Author(s):  
Dumitru Bolcu ◽  
Marius Marinel Stănescu ◽  
Cosmin Mihai Miriţoiu ◽  
Cristian Oliviu Burada
Keyword(s):  
External Force ◽  
Natural Fibers ◽  
Free Vibrations ◽  
Vibration Damping ◽  
Initial Deformation ◽  
Rectangular Section ◽  
Hemp Fibers ◽  
Free Length ◽  
Natural Resin

In this paper we have studied the vibration damping for composite bars made by dammar based natural resin, the reinforcement being made by flax, cotton, silk and hemp fibers. There were made rectangular section samples (5x10 mm) with 220 mm length. The bars were clamped, the free length being 100 mm, 120 mm, 140 mm, 160 mm and 180 mm. For each bar, the free vibrations made by an initial deformation, obtained by inserting an external force in the free end, were recorded. In each case, the measured vibration was under-damped.

Seismic Testing Program for Large-Scale MSE Retaining Walls at UCSD

2013 ◽  
Author(s):  
Andrew C. Sander ◽  
Patrick J. Fox ◽  
Ahmed Elgamal ◽  
Daniel E. Pradel ◽  
Daniel Isaacs ◽  
...  
Keyword(s):  
Large Scale ◽  
Retaining Walls ◽  
Testing Program ◽  
Seismic Testing

scholarly journals Environmental concerns delay seismic testing

Nature ◽  
2009 ◽  
Vol 460 (7258) ◽  
pp. 939-939
Author(s):  
Rex Dalton
Keyword(s):  
Environmental Concerns ◽  
Seismic Testing
Sign in / Sign up

Export Citation Format

Share Document