Behaviour of square concrete filled FRP tube columns under concentric, uniaxial eccentric, biaxial eccentric and four-point bending loads

2021 ◽  
Vol 168 ◽  
pp. 108252
Author(s):  
Radwan A. Alelaimat ◽  
M. Neaz Sheikh ◽  
Muhammad N.S. Hadi
Author(s):  
B. K. Dutta ◽  
Shekhar Saini ◽  
Navneet Arora

The mesh dependency of Rice and Tracey cavity growth factor (CGF) is overcome by integrating the CGF over a process zone surrounding the crack tip. This integral represents a modified damage potential. The critical value of the integral for crack initiation in weld material has been determined analyzing a welded CT specimen and comparing the computed crack initiation J with experimentally measured J-initiation value. This critical value is then employed to predict crack initiation load in 8” and 12” welded pipes having different measure of through-wall cracks at the center to predict the loads under four point bending loads. The computed values are compared with the experimentally measured values. A close agreement between the computed crack initiation loads with the experimentally measured values justifies the usefulness of the present modified damage potential.


Author(s):  
Claudia Zindl ◽  
Noel Fitzpatrick ◽  
Alan S. Litsky ◽  
Matthew J. Allen

Abstract Objective The aim of this study was to determine the biomechanical behaviour of a novel distraction–fusion system, consisting of an intervertebral distraction screw, pedicle locking screws and connecting rods, in the canine caudal cervical spine. Study Design Biomechanical study in cadaveric canine cervicothoracic (C3–T3) spines (n = 6). Cadaveric spines were harvested, stripped of musculature, mounted on a four-point bending jig, and tested using non-destructive four-point bending loads in extension (0–100 N), flexion (0–60 N) and lateral bending (0–40 N). Angular displacement was recorded from reflective optical trackers rigidly secured to C5, C6 and C7. Data for primary and coupled motions were collected from intact spines and following surgical stabilization (after ventral annulotomy and nucleotomy) with the new implant system. Results As compared with the intact spine, instrumentation significantly reduced motion at the operated level (C5-C6) with a concomitant non-significant increase at the adjacent level (C6-C7). Conclusion The combination of a locking pedicle screw-rod system and intervertebral spacer provides an alternative solution for surgical distraction–stabilization in the canine caudal cervical spine and supports the feasibility of using this new implant system in the management of disc-associated cervical spondylomyelopathy in dogs. The increase in motion at C6-C7 may suggest the potential for adjacent level effects and clinical trials should be designed to address this.


2019 ◽  
Vol 141 (6) ◽  
Author(s):  
R. W. Bianchi ◽  
Y. W. Kwon ◽  
E. S. Alley

Both experimental and numerical studies were conducted to investigate the effectiveness of composite patch repair on underwater structures, especially aluminum alloy structures. Physical samples were prepared using 5XXX aluminum plates with a premachined hole and E-glass woven fabric layers. The epoxy resin was selected such that it could be cured underwater. Test samples were prepared under different curing conditions such as dry curing and wet curing with different durations of in-water exposure. Strain gages were attached to all samples. The samples were tested for both tensile and four-point bending loads. Furthermore, numerical modeling and simulations were conducted, and the numerical models were validated against the experimental measurements. Then, the interface normal and shear stresses were determined from the numerical models so as to understand the delamination failure at the interface between the aluminum and composite patches. Underwater composite patching showed good interface strength and potential for successful usage in repairs.


1967 ◽  
Vol 9 (5) ◽  
pp. 355-361 ◽  
Author(s):  
R. M. Ogorkiewicz ◽  
A. A. M. Sayigh

Design of plastics sandwich structures calls for methods of predicting their deformation under load, which were studied with particular reference to beams under three- and four-point bending and under uniformly distributed loads. A preliminary series of tests established the stress-strain characteristics of p.v.c. (polyvinyl chloride) and polyurethane core and rigid p.v.c. skin materials. Using stress function solutions deflections and skin strains of different beams of these materials were then calculated and compared with experimental results obtained with beams made of the same combinations of materials. Good agreement was found for loads of short duration within the limits imposed by local stress concentrations.


2013 ◽  
Vol 594-595 ◽  
pp. 416-420 ◽  
Author(s):  
Li Bo Yan ◽  
Nawawi Chouw ◽  
Krishnan Jayaraman

The compressive and flexural performance of flax fibre reinforced polymer (FFRP) confined coconut fibre reinforced concrete (CFRC) structures were investigated. The mass content of coconut fibre considered was 1% of cement. Eighteen cylinders were tested under uniaxial compression and 12 beams were tested under four-point bending. Test results show that in compression, both FFRP tube and FFRP wrapping confinements enhance the axial compressive strength and ultimate strain of concrete significantly, e.g. the ultimate strength of 4-layer FFRP tube confined CFRC is 94% larger than that of the unconfined CFRC. In flexure, the FFRP tube increases the lateral load bearing capacity and the deflection several times larger than the unconfined concrete columns, e.g. the ultimate lateral load of 4-layer FFRP confined PC and CFRC are 1066% and 946% larger than the corresponding unconfined PC and CFRC specimens. In flexure, coir inclusion can affect the failure mode of the FFRP-CFRC composite structure significantly.


A study review of aging polymer composite materials (PCM) under different heat-moisture conditions or water exposure with the sequential or parallel influence of static or cyclic loads in laboratory conditions is presented. The influence of tension and bending loads is compared. Conditions of the different load influence on parameters of carbon-reinforced plastics and glass-reinforced plastics are discussed. Equipment and units for climatic tests of PCM under loading are described. Simulation examples of indices of mechanical properties of PCM under the influence of environment and loads are shown.


A study review of aging polymer composite materials (PCM) under different heat-moisture conditions or water exposure with the sequential or parallel influence of static or cyclic loads in laboratory conditions is presented. The influence of tension and bending loads is compared. Conditions of the different load influence on parameters of carbon-reinforced plastics and glass-reinforced plastics are discussed. Equipment and units for climatic tests of PCM under loading are described. Simulation examples of indices of mechanical properties of PCM under the influence of environment and loads are shown.


2009 ◽  
Vol 51 (9) ◽  
pp. 580-586 ◽  
Author(s):  
Bernd Oberwinkler ◽  
Martin Riedler ◽  
Heinz Leitner ◽  
Ataollah Javidi

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