Overall buckling prediction model for fibre reinforced plastic laminated tubes with balanced off-axis ply orientations based on Puck failure criteria

2019 ◽  
Vol 54 (7) ◽  
pp. 883-897 ◽  
Author(s):  
Ruoyu Li ◽  
Ruijie Zhu ◽  
Feng Li
Keyword(s):  
Prediction Model ◽  
Axial Compression ◽  
Transverse Shear ◽  
Failure Modes ◽  
Failure Criteria ◽  
Shear Effect ◽  
Compression Tests ◽  
Reinforced Plastic ◽  
Overall Buckling ◽  
Ply Orientation

Fibre reinforced plastic tubes with balanced off-axis ply orientation exhibit excellent mechanical properties and are widely used in various types of structures. In this study, a theoretical prediction model was proposed to determine the overall buckling load and the failure mode of fibre reinforced plastic laminated tubes with off-axis ply orientation under axial compression. This model considers the transverse shear effect and adopts Puck failure criteria to perform an analysis based on deduced three-dimensional stress and strain fields. A series of carbon fibre reinforced plastics tubes with varying off-axis ply orientations and lengths were designed and prepared. Axial compression tests with effective end-reinforcement and hinge support were performed to validate the proposed prediction model. The results indicated that the predicted model results were in good agreement with the test results, with respect to ultimate loads, failure modes, and locations of failure. Parametric analysis on the influence of transverse shear effect was also conducted, which further explained the influencing degree of transverse shear effect considering different tube lengths, ply sequences, and initial deflection.

scholarly journals Study on the Mechanical Properties of BFRP Tube Confined Concrete Short Columns under Axial Compression

2020 ◽  
Author(s):  
Xindong Ding ◽  
Shuqing Wang ◽  
Yu Liu ◽  
Zepeng Zheng
Keyword(s):  
Axial Compression ◽  
Brittle Failure ◽  
Failure Modes ◽  
Concrete Strength ◽  
Steel Tube ◽  
Confined Concrete ◽  
Test Results ◽  
Compression Tests ◽  
Short Columns ◽  
Square Steel Tube

Axial compression tests were carried out on 6 square steel tube confined concrete short columns and 6 BFRP square pipe confined concrete axial compression tests. The concrete strength grades were C30, C40, and C50. The test results show that the failure modes of steel pipe and BFRP pipe are obviously different, and the BFRP pipe undergoes brittle failure. Compared with the short columns of concrete confined by BFRP pipes, the ultimate bearing capacity of axial compression is increased by -76.46%, -76.01%, and -73.06%, and the ultimate displacements are -79.20%, -80.78%, -71.71%.

scholarly journals EXPERIMENTAL COMPRESSION TESTS OF COLD-FORMED STEEL (CFS) TO VERIFY ITS CODE-BASED STRENGTH

2021 ◽  
Vol 10 (2) ◽  
Author(s):  
Bernardo Lejano ◽  
James Matthew De Jesus ◽  
Arvin Patrick Yu
Keyword(s):  
Axial Compression ◽  
High Speed ◽  
Failure Modes ◽  
Weight Ratio ◽  
The Philippines ◽  
Structural Performance ◽  
Computational Aspect ◽  
Compression Tests ◽  
Flexural Buckling ◽  
Cold Formed Steel

Cold-Formed Steel (CFS) is a good construction material because of its high strength-to-weight ratio, that is, it exhibits efficient load carrying capabilities in combination with its lightweight characteristics. Although CFS is already being used in construction, information on structural performance of locally-produced CFS in the Philippines is scarce. To date, the authors have not found any experimental study done in the Philippines regarding the structural performance of locally-produced CFS. In this study, C-section and Z-section are being studied since these members exhibit buckling failures that may be difficult to predict due to complexity of their section geometry. The objective of this paper is to present the performance of these CFS sections when subjected to concentric axial compression both experimentally and computationally. For the experimental part, the CFS members were subjected to axial compression using a hydraulic jack. High-speed video cameras were used to capture the different failure modes. For the computational aspect, provisions found in the National Structural Code of the Philippines (NSCP) were used to calculate the compression strength of the members. A total of 80 C-section specimens with 5 different lengths and 5 different thicknesses were tested. It was found that the strength calculations using the NSCP provisions were not consistent with the results of the compression tests. For shorter lengths, distortional buckling prevailed as the main failure, while for longer lengths, torsional-flexural buckling occurred. All of the predicted strengths were highly conservative. For the Z-section, a total of 180 specimens with 6 different lengths and 6 different thicknesses were tested. Torsional-flexural buckling was observed in majority of the specimens. Although most of the failure modes were predicted correctly, it was found that the predicted strengths using the NSCP were relatively high compared to the experimental results, thus non-conservative. Finite Element Method (FEM) analyses using ANSYS were conducted. Findings indicate that the experiment results agreed well with the FEM results.

Experimental Study on Axial Compression Performance of High-Strength Aluminum-Alloy Columns with H-Section

2013 ◽  
Vol 274 ◽  
pp. 459-462 ◽  
Author(s):  
Feng Fan ◽  
Yu Jin Wang ◽  
Li Lin ◽  
Hong Liang Qian
Keyword(s):  
Aluminum Alloy ◽  
Axial Compression ◽  
Failure Modes ◽  
High Strength ◽  
Tensile Tests ◽  
Test Program ◽  
Column Tests ◽  
Compression Performance ◽  
Heat Treated ◽  
Overall Buckling

This paper presents an experimental investigation of aluminum alloy H-type sections subjected to axial compression between two pinned ends. The specimens were fabricated using 6082-T6 heat-treated aluminum alloy. 26 material tensile tests were performed then a test program included 12 column tests which were separated into 6 test series of different geometry and ranged from 990 to 1840 mm in length in order to obtain a column curve. All the observed failure modes for the column tests were overall buckling and the axial capacities were obtained.

scholarly journals Study on the Mechanical Properties of BFRP Tube Confined Concrete Short Columns under Axial Compression

2020 ◽  
Author(s):  
Xindong DING ◽  
Shuqing Wang ◽  
Yu Liu ◽  
Zepeng Zheng
Keyword(s):  
Axial Compression ◽  
Brittle Failure ◽  
Failure Modes ◽  
Concrete Strength ◽  
Steel Tube ◽  
Confined Concrete ◽  
Test Results ◽  
Compression Tests ◽  
Short Columns ◽  
Square Steel Tube

Axial compression tests were carried out on 6 square steel tube confined concrete short columns and 6 BFRP square pipe confined concrete axial compression tests. The concrete strength grades were C30, C40, and C50. The test results show that the failure modes of steel pipe and BFRP pipe are obviously different, and the BFRP pipe undergoes brittle failure. Compared with the short columns of concrete confined by BFRP pipes, the ultimate bearing capacity of axial compression is increased by -76.46%, -76.01%, and -73.06%, and the ultimate displacements are -79.20%, -80.78%, -71.71%.

scholarly journals An Enhanced Ubiquitous-Joint Model for a Rock Mass With Conjugate Joints and Its Application on Excavation Simulation of Large Underground Caverns

2021 ◽  
Vol 9 ◽  
Author(s):  
Xianlun Leng ◽  
Chuan Wang ◽  
Qian Sheng ◽  
Jian Chen ◽  
Hailun Li
Keyword(s):  
Rock Mass ◽  
Failure Modes ◽  
Triaxial Compression ◽  
Local Coordinate System ◽  
Failure Criteria ◽  
Jointed Rock ◽  
Joint Model ◽  
Compression Tests ◽  
Mechanical Behaviors ◽  
Underground Caverns

A conjugate jointed rock mass (CJRM) is a rock mass with two sets of intersecting joints formed from intact rock under shear. Its mechanical properties and excavation-induced hazards of large underground caverns are different from those of common rock masses because of the unique geological origin thereof. To demonstrate numerically the excavation responses of CJRM, the ubiquitous-joint model is enhanced by consideration of the specific mechanical behaviors of the rock mass. In the enhanced model, CJRM is considered as the composite of columns of rock and two sets of weak planes of joints. The local coordinates, failure modes, and failure sequences of the rock columns and joints are redefined based on the composite characteristics of CJRM, and the failure criteria and plastic potential functions are accordingly modified. The enhanced model is verified numerically by triaxial compression tests and then employed to simulate the excavation of large underground caverns of a pumped storage power station in China. Results show that the modification of the local coordinate system, failure modes, and failure sequences made in the enhanced model is suited to the simulation of the mechanical behaviors of CJRM. Compared with the original ubiquitous-joint model, the enhanced model allows better predictions of the distribution of plastic zones and magnitudes of deformations in simulating underground excavations in CJRM and helps to assess the excavation-triggered hazards more accurately.

scholarly journals Overall buckling behaviour of laminated CFRP tubes with off-axis ply orientation in axial compression

2019 ◽  
Vol 26 (1) ◽  
pp. 230-239 ◽  
Author(s):  
Ruijie Zhu ◽  
Feng Li ◽  
Dongdong Zhang
Keyword(s):  
Axial Compression ◽  
Test Data ◽  
Slenderness Ratio ◽  
High Stress ◽  
Reduction Factor ◽  
Compression Tests ◽  
Future Design ◽  
High Stress Level ◽  
Cfrp Tubes ◽  
Overall Buckling

AbstractThis paper presents an experimental investigation of overall buckling behaviour of carbon fibre reinforced plastic (CFRP) tubes with different off-axis ply orientations. A series of specimens are designed and prepared with stacking sequences [0∘4/±θ∘], with θ corresponding to either 0, 90, 45 or 60. Axial compression tests with effective end-reinforcement and hinge support are performed to investigate the overall buckling behaviour. With respect to the future design and application of CFRP tubes with this type of stacking sequence, column curves for each stacking sequences and all test data are fitted based on Perry-Robertson formula. With respect to the high stress level in the relatively short CFRP tube that facilitates the development of defects, test data present high levels of discreetness. We propose a strategy for engineering safe design in which a reduction factor is added to the original reduction factor based on statistical analysis when the universal slenderness ratio is less than 2.

scholarly journals Axial Compression Performance of Post-Fire Concrete Columns Strengthened Using Thin-Walled Steel Tubes

2019 ◽  
Vol 11 (18) ◽  
pp. 4971
Author(s):  
Luo ◽  
Su ◽  
Xu ◽  
Ou ◽  
Peng
Keyword(s):  
Axial Compression ◽  
Failure Modes ◽  
Shear Failure ◽  
Concrete Columns ◽  
Thin Wall ◽  
Compression Tests ◽  
Steel Tubes ◽  
Compression Performance ◽  
Ultimate Deformation ◽  
Thin Walled

For concrete columns damaged by fire, a strengthen technique using thin-walled steel tubes is proposed. To investigate the axial compression capacity of post-fire concrete columns strengthened using thin-walled steel tubes, considering tube thickness, the strengthening method, and section geometry, 12 specimens were fabricated, of which two were control columns and 10 were exposed to fire in accordance with the ISO834 temperature curve. Subsequently, eight specimens were strengthened. Axial compression tests were conducted to provide a better understanding of the strengthening technique. The experiments indicated that: (1) Different failure modes were observed for different cross section geometry—local bucking for square sections, and shear failure for circular sections. (2) The stiffness, axial strength, and ultimate deformation capacity of the enhanced columns may be rehabilitated and even better than the undamaged ones. (3) Two enhancement methods were compared. The steel tubes act as restraints, are merely subjected to tension, and provide strong restraint to the core concrete. The tube carrying load together with the concrete columns are mainly subject to compression, and likely to buckle with longitudinal strain. Finally, axial compressive equations of post-fire reinforced concrete (RC) with thin-wall steel tubes, including both square sections and circle sections, were proposed on the mechanism of concrete filled steel tubes.

Influence of off-axis ply orientation on the axial compression behaviour of CFRP tubes

2016 ◽  
Vol 36 (6) ◽  
pp. 399-413
Author(s):  
Jie Tao ◽  
Feng Li ◽  
Qilin Zhao ◽  
Dongdong Zhang
Keyword(s):  
High Speed ◽  
Failure Modes ◽  
Shear Failure ◽  
Shear Fracture ◽  
Gauge Length ◽  
Compression Tests ◽  
Average Value ◽  
Compression Behaviour ◽  
Cfrp Tubes ◽  
Ply Orientation

This paper presents an experimental investigation of the compression behaviour of Carbon Fiber Reinforced Plastics (CFRP) tubes with different off-axis ply orientations. A series of compression tests with effective end-reinforcement were conducted on [04/±theta] CFRP tubes, with θ equal to either 0°, 30°, 45°, 60°, or 90°. Various failure progressions and fracture morphologies were measured using a high-speed camera and a scanning electron microscope. The failure modes and mechanisms of CFRP tubes with different stacking sequences were analysed in detail. The results indicate that the off-axis ply orientation greatly influences the compression behaviour. The adopted end-reinforcement ensures that nearly all of the CFRP tubes fail within the gauge length. When θ < 45°, the tubes exhibit various failure modes, and the scatter of strength is large. However, when θ ≥ 45°, the sole failure mode is a shear fracture of the inner 0° layers, and their scatter of strength is minor. A new shear failure mechanism is instrumented: the shear fracture direction changes from inclining along the circumferential direction to inclining along the radial direction when θ varies from 45° to 90°. The failure strength and off-axis ply orientation display a complex non-linear relationship. When θ = 60°, the compression strength becomes maximum at an average value of 602 MPa, and the scatter of strength is 2.71%.

scholarly journals Axial Compression Behaviours of Pultruded GFRP–Wood Composite Columns

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 755 ◽  
Author(s):  
Yujun Qi ◽  
Lei Xie ◽  
Yu Bai ◽  
Weiqing Liu ◽  
Hai Fang
Keyword(s):  
Axial Compression ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Slenderness Ratio ◽  
Experimental Investigations ◽  
Wood Composite ◽  
Compression Tests ◽  
Element Analysis ◽  
Load Bearing ◽  
Global Buckling

An innovative pultruded fiber reinforced polymer (FRP)–wood composite (PFWC) column with a lightweight southern pine wood core confined by outer FRP sheets was manufactured using an improved pultrusion process. Axial compression tests with both ends pinned as boundary conditions were employed to investigate the mechanical performance of such PFWC columns under concentric load. Through experimental investigations, the effects of the slenderness ratio on the failure modes and the axial load bearing capacities of the PFWC columns were evaluated. The failure modes showed that the specimens with a slenderness ratio less than 43.2 failed through compressive failure at junctions on FRP sheets, while those with slenderness ratios larger than 57.6 showed global buckling. Strain responses on specimens with different slenderness ratios are consistent with the observed failure modes. Finite element analysis was carried out to validate the experimental results, and satisfactory agreement was found between the failure modes and load–displacement curves. An empirical equation was developed with a new factor taking 0.65 into account to predict the load bearing capacities of the PFWC columns, and good agreement was found.

Towards Optimum Carbon-Fibre-Reinforced Plastic End Closures

1991 ◽  
Vol 205 (5) ◽  
pp. 329-342 ◽  
Author(s):  
J Błachut ◽  
G D Galletly ◽  
F Levy-Neto
Keyword(s):  
Carbon Fibre ◽  
Failure Modes ◽  
Failure Criteria ◽  
External Pressure ◽  
Finite Deflection ◽  
Shell Buckling ◽  
Reinforced Plastic ◽  
Bifurcation Buckling ◽  
Pressure Tests ◽  
Carbon Fibre Reinforced Plastic

Two series of external pressure tests on six-layer CFRP (carbon-fibre-reinforced plastic) torispherical domes are discussed in the paper. One series had a diameter-average thickness ratio of 80 and the other 120. The ratio Rs/D was the same for all the models and equalled 0.55 (Rs = spherical radius of a dome). The ratio r/D (r = toroidal or knuckle radius) varied from 0.2 to 0.5, the latter being a hemisphere. All the models were made by the hand lay-up/vacuum bag technique using male moulds. The failure modes considered were bifurcation buckling and first-ply failure (FPF). The BOSOR 4 program was used to evaluate the theoretical stresses in the shells and various failure criteria (Owen, Tsai-Wu etc.) were employed to determine the FPF pressures. In the tests, all the models failed by material failure rather than shell buckling and the ratios of the experimental collapse pressures to the FPF predictions were in the range 0.85–1.30. The tests also confirm a recent theoretical prediction that there is an optimum value of the r/D ratio insofar as dome strength is concerned. These CFRP torispherical domes are lighter and stronger than the comparable CFRP hemispheres. The BOSOR 4 predictions of FPF pressures and failure locations were confirmed by the NISA finite element code. The calculations also showed that it is necessary to use finite deflection shell theory when analysing these composite domes.

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