scholarly journals The Effect of Stacking Sequence on Fatigue Behaviour of Hybrid Pineapple Leaf Fibre/Carbon-Fibre-Reinforced Epoxy Composites

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3936
Author(s):  
Mohd Khairul Rabani Hashim ◽  
Mohd Shukry Abdul Majid ◽  
Mohd Ridzuan Mohd Jamir ◽  
Farizul Hafiz Kasim ◽  
Mohamed Thariq Hameed Sultan ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Failure Modes ◽  
High Stress ◽  
Tensile Load ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Matrix Cracking ◽  
Stacking Sequence ◽  
Fibre Breakage ◽  
Pull Out

This study examined the fatigue behaviour of pineapple leaf fibre/carbon hybrid laminate composites under various stacking sequences. The vacuum infusion technique was used to fabricate the symmetric quasi-isotropic oriented laminates, in which the stacking was varied. The laminate was tested under static and fatigue tensile load according to ASTM D3039-76 and ASTM D3479-96, respectively. Maximum tensile strength and modulus of 119.34 MPa and 6.86 GPa, respectively, were recorded for the laminate with external PALF ply and internal carbon ply oriented at [± 45°2, 0°/90°2]s (PCCP_45090). The fatigue tests showed that PCCP_45090 and CPPC_09045 (with internal PALF ply and external carbon ply oriented at [0°/90°2, ± 45°2]s) exhibited a higher useful life, especially at the high-stress level of the ultimate tensile strength. The normalised stress against the number of cycles showed that the stacking sequences of different ply orientations affected the fatigue behaviour more than the stacking sequences of the material. The laminate stacking sequence significantly affected the hysteresis energy and stiffness evolution. The scanning electron microscopy images showed that the fatigue failure modes included fibre pull-out, fibre breakage, matrix cracking, debonding, and delamination. The study concluded that PCCP_45090 exhibited an outstanding fatigue performance.

scholarly journals Falling Weight Impact Damage Characterisation of Flax and Flax Basalt Vinyl Ester Hybrid Composites

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 806 ◽  
Author(s):  
Hom Nath Dhakal ◽  
Elwan Le Méner ◽  
Marc Feldner ◽  
Chulin Jiang ◽  
Zhongyi Zhang
Keyword(s):  
Vinyl Ester ◽  
Failure Modes ◽  
Hybrid Composites ◽  
Impact Damage ◽  
Matrix Cracking ◽  
Damage Mechanisms ◽  
Pull Out ◽  
Weight Impact ◽  
Falling Weight ◽  
The Impact

Understanding the damage mechanisms of composite materials requires detailed mapping of the failure behaviour using reliable techniques. This research focuses on an evaluation of the low-velocity falling weight impact damage behaviour of flax-basalt/vinyl ester (VE) hybrid composites. Incident impact energies under three different energy levels (50, 60, and 70 Joules) were employed to cause complete perforation in order to characterise different impact damage parameters, such as energy absorption characteristics, and damage modes and mechanisms. In addition, the water absorption behaviour of flax and flax basalt hybrid composites and its effects on the impact damage performance were also investigated. All the samples subjected to different incident energies were characterised using non-destructive techniques, such as scanning electron microscopy (SEM) and X-ray computed micro-tomography (πCT), to assess the damage mechanisms of studied flax/VE and flax/basalt/VE hybrid composites. The experimental results showed that the basalt hybrid system had a high impact energy and peak load compared to the flax/VE composite without hybridisation, indicating that a hybrid approach is a promising strategy for enhancing the toughness properties of natural fibre composites. The πCT and SEM images revealed that the failure modes observed for flax and flax basalt hybrid composites were a combination of matrix cracking, delamination, fibre breakage, and fibre pull out.

Development of Splice Connections for Precast Concrete Structures

2014 ◽  
Vol 980 ◽  
pp. 132-136 ◽  
Author(s):  
Ahmad Baharuddin Abd Rahman ◽  
Jen Hua Ling ◽  
Zuhairi Abd Hamid ◽  
Mohd Hanim Osman ◽  
Shahrin Mohammad ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Failure Modes ◽  
Ultimate Load ◽  
Precast Concrete ◽  
Tensile Load ◽  
Test Results ◽  
Steel Bars ◽  
Embedment Length ◽  
Bar Diameter

This paper presents the test results of proposed grouted sleeve connections under increasing tensile load. The objective of this research was to investigate splice connections that could provide tensile strength similar to the full tensile strength of the connected rebars. The parameters varied were splice types, splice length and rebar embedment length. The performance of the splice connection was evaluated based on the load-displacement, ultimate load, displacements and failure modes. The results show that the strength of splice connection depends on the bond strength between sleeve-to-grout and grout-to-rebar; the tensile strength of spliced steel bars and also the tensile strength of sleeve. It is observed that when the grout compressive strength is more than 60N/mm2and bar embedded length is at least 10 bar diameter, the splice connection in BS series is able to provide full tensile strength of the connected rebars.

scholarly journals Experimental and numerical investigation of the overload effect on fatigue behaviour of spot-welded steel sheets

2018 ◽  
Vol 106 (3) ◽  
pp. 309 ◽  
Author(s):  
Fabienne Pennec ◽  
Bianzeubé Tikri ◽  
Sébastien Bergamo ◽  
Michel Duchet ◽  
Bastien Weber ◽  
...  
Keyword(s):  
Failure Modes ◽  
Hsla Steel ◽  
High Strength ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Favourable Effect ◽  
Low Alloy Steels ◽  
Element Analysis ◽  
Alloy Steels ◽  
Spot Welded

Spot-weld joints are commonly used to fasten together metal sheets in automotive industry. The car frame used in Renault vehicles is a representative example of the usefulness of this method. Most of the spot-welds experience fatigue damaging occurrence due to rough roads or driving conditions which apply periodical overloads to the vehicle. Understanding their fatigue behaviour is crucial from the viewpoint of failure prevention in design. In this study, a series of experiments was conducted to study the fatigue failure of spot-welded tensile-shear specimens made of a deep-drawing steel (XES) and High strength low alloy steels (HE360D and XE360D). Two different types of fatigue tests were performed, the first one with a constant-amplitude sinusoidal loading (loading ratio equal to 0.1) and the second one with one incidental overload cycle introduced per 100 cycles. The experimental results show a favourable effect of overloads for HSLA steel specimens, whereas the effect is the opposite for XES steel specimens. A finite element analysis was carried out using the open-source Salome-Meca platform to determine the stress states within the specimens around the weld spot and explains both failure modes observed on the specimens at high and low loads.

Temperature effects on transverse failure modes of carbon fiber/bismaleimides composites

2016 ◽  
Vol 51 (2) ◽  
pp. 261-272 ◽  
Author(s):  
Baifeng Yang ◽  
Zhufeng Yue ◽  
Xiaoliang Geng ◽  
Peiyan Wang
Keyword(s):  
Carbon Fiber ◽  
Room Temperature ◽  
Failure Modes ◽  
High Stress ◽  
Tensile Load ◽  
Plastic Behavior ◽  
Electron Microscopic ◽  
Transverse Tensile ◽  
Analytical Results ◽  
Transverse Failure

The results of experimental and numerical studies on temperature dependence of carbon fiber/bismaleimides composites subjected to transverse tensile load at −120℃, 25℃, 150℃, 170℃, 200℃ are summarized. The scanning electron microscopic fractographs showed that fibers were coated by a small amount of resin along with split resin at −120℃, melted resin attached to fibers is found in the view at 200℃ and naked fibers were observed at room temperature. It is concluded that the interfacial strength reduced with the increase of temperature. Experimental stress versus strain curves showed that modulus decreased with the increase of the temperature, and the obviously nonlinear tendency was observed at 200℃. Employed Mohr–Coulomb criterion to characterize plastic behavior of bismaleimides matrix, representative volume element based on random sequential expansion algorithm was modeled to simulate the entire damage progress with thermomechanical load. The analytical results showed that high stress concentration occurred in the matrix band between closely arranged fibers and became more severe with temperature rising. The percentage of interfacial debonding was larger at room temperature than those at higher and lower temperature. The experimental and analytical results showed that transverse failure modes at different temperature are related to thermal residual stress and the Young’s module of matrix.

scholarly journals Study on Mechanical Features of Brazilian Splitting Fatigue Tests of Salt Rock

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Weichao Wang ◽  
Mengmeng Wang ◽  
Xiliang Liu
Keyword(s):  
Tensile Strength ◽  
Failure Modes ◽  
Splitting Method ◽  
Fatigue Tests ◽  
Test Machine ◽  
Salt Rock ◽  
Tablet Splitting ◽  
Splitting Test ◽  
Fracturing Process ◽  
Brazilian Splitting

The microtest, SEM, was carried out to study the fracture surface of salt rock after the Brazilian splitting test and splitting fatigue test were carried out with a servo-controlled test machine RMT-150B. The results indicate that the deviation of using the tablet splitting method is larger than that of using steel wire splitting method, in Brazilian splitting test of salt rock, when the conventional data processing method is adopted. There are similar deformation features in both the conventional splitting tests and uniaxial compression tests. The stress-strain curves include compaction, elasticity, yielding, and failure stage. Both the vertical deformation and horizontal deformation of splitting fatigue tests under constant average loading can be divided into three stages of “loosening-tightness-loosening.” The failure modes of splitting fatigue tests under the variational average loading are not controlled by the fracturing process curve of the conventional splitting tests. The deformation extent of fatigue tests under variational average loading is even greater than that of conventional splitting test. The tensile strength of salt rock has a relationship with crystallization conditions. Tensile strength of thick crystal salt rock is lower than the bonded strength of fine-grain crystals.

Investigation on Effect of Varying Weight Percentage of Glass Fiber and Filler on the Properties of Glass Fiber-Cement- Polyester Composites

2020 ◽  
Vol 995 ◽  
pp. 117-122
Author(s):  
Phaneesh Shettigar ◽  
Manjunath Shettar ◽  
Rao U. Sathish ◽  
C.S. Suhas Kowshik ◽  
M.C. Gowrishankar
Keyword(s):  
Tensile Strength ◽  
Flexural Strength ◽  
Glass Fiber ◽  
Polyester Resin ◽  
Tensile Load ◽  
Weight Percentage ◽  
Pull Out ◽  
The Matrix ◽  
Polyester Composites

In this research, the results of different weight percentage of glass fiber (30, 40 & 50), cement (0, 3 & 6) and polyester resin (70, 60 & 50), on the properties of glass fiber-cement-polyester composites are investigated. The specimens are prepared by hand lay-up technique. All the specimens are tested for tensile and flexural strength as per ASTM standards. Results showed that escalation in glass fiber wt.% improved the tensile strength (by 9% at 40 wt.% and 17% at 50 wt.%) and flexural strength (by 10% at 40 wt.% and 16.5% at 50 wt.%). Whereas an increase in cement weight percentage decreases tensile strength and increases flexural strength. The failure of the sample is due to glass fiber pull out and rupture of the matrix, under tensile load.

scholarly journals Effect of Hybridization on the Mechanical Properties of Chopped Strand Mat/Pineapple Leaf Fibre Reinforced Polyester Composites

2018 ◽  
Vol 153 ◽  
pp. 01006 ◽  
Author(s):  
Suhas Yeshwant Nayak ◽  
Srinivas Shenoy Heckadka ◽  
Nishank Minil Amin ◽  
Ramakrishna Vikas Sadanand ◽  
Linto George Thomas
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Flexural Strength ◽  
Polymer Composites ◽  
Matrix Cracking ◽  
Reinforced Composites ◽  
Pull Out ◽  
The Matrix ◽  
Chopped Strand Mat ◽  
Hybrid Laminate

Hybridization of synthetic and natural fibres as reinforcement makes the polymer composites environmental friendly and sustainable when compared to synthetic fibres based polymer composites. In this study chopped strand mat/pineapple leaf fibres were hybridized. Four laminates with six layers each, with different stack sequence (GGGGGG, GPPPPG, PGGGGP and PPPPPP) were fabricated using hand layup technique while maintaining a fibre to matrix ratio of 30:70 by weight with polyester resin as matrix. Mechanical properties such as tensile and flexural strength were determined and morphology of fractured specimens was studied. Maximum tensile strength of 180 MPa was obtained for the laminate with six layers of chopped strand mat followed by hybrid laminate with four layers of chopped strand mat at the centre (120 MPa). Tensile strength of hybrid laminate with four layers of pineapple leaf fibres at the centre was in third position at 86 MPa. Least tensile strength of 65 MPa was obtained for the laminate with six layers of pineapple leaf fibres. Similar trend was observed in case of flexural behaviour of the laminates with maximum flexural strength of 255 MPa and minimum flexural strength 107 MPa. Scanning electron microscopy of the fractured specimen reinforced with chopped strand mat only, indicated, fibre pull out, matrix cracking and lack of matrix adhesion to fibres. In case of hybrid composite (GPPPPG and PGGGGP) delamination was observed to be prominent due to improper wetting of the pineapple leaf fibres with the matrix. More significant delamination led to lesser strength in case of pineapple fibres reinforced composites even though the fibre pull out was relatively less.

scholarly journals The Effect of Stacking Sequence and Ply Orientation on the Mechanical Properties of Pineapple Leaf Fibre (PALF)/Carbon Hybrid Laminate Composites

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 455
Author(s):  
Mohd Khairul Rabani Hashim ◽  
Mohd Shukry Abdul Majid ◽  
Mohd Ridzuan Mohd Jamir ◽  
Farizul Hafiz Kasim ◽  
Mohamed Thariq Hameed Sultan
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Stacking Sequence ◽  
Laminate Composites ◽  
Pull Out ◽  
Hybrid Laminates ◽  
Flexural Tests ◽  
Infusion Technique ◽  
Ply Orientation ◽  
Hybrid Laminate

In this paper, the effects of stacking sequence and ply orientation on the mechanical properties of pineapple leaf fibre (PALF)/carbon hybrid laminate composites were investigated. The hybrid laminates were fabricated using a vacuum infusion technique in which the stacking sequences and ply orientations were varied, which were divided into the categories of cross-ply symmetric, angle-ply symmetric, and symmetric quasi-isotropic. The results of tensile and flexural tests showed that the laminate with interior carbon plies and ply orientation [0°, 90°] exhibited the highest tensile strength (187.67 MPa) and modulus (5.23 GPa). However, the highest flexural strength (289.46 MPa) and modulus (4.82 GPa) were recorded for the laminate with exterior carbon plies and the same ply orientation. The fracture behaviour of the laminates was determined by using scanning electron microscopy, and the results showed that failure usually initiated at the weakest PALF layer. The failure modes included fibre pull-out, fibre breaking, matrix crack, debonding, and delamination.

Cumulative Seismic Damage of Reinforced Concrete Columns: Benchmark and Low-Cycle Fatigue Tests

2011 ◽  
Vol 52-54 ◽  
pp. 734-739 ◽  
Author(s):  
Yuan Pan ◽  
Guo Hua Xing ◽  
Guo Fu ◽  
Jian Ling Hou
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Low Cycle Fatigue ◽  
High Stress ◽  
Concrete Columns ◽  
Companion Paper ◽  
Fatigue Tests ◽  
Cumulative Damage ◽  
Cycle Fatigue ◽  
Reinforced Concrete Columns

Under seismic actions, reinforced concrete columns are generally damaged by a combination of repeated stress reversals and high stress excursions. An experimental study was undertaken to investigate cumulative damage in reinforced concrete rectangular columns subjected to repeated cyclic loadings. Fourteen identical half-scale concrete columns were fabricated and tested to failure. This paper summarizes the results of Phase I testing that consisted of benchmark tests to establish the monotonic force-deformation envelope, and constant amplitude tests to determine the low-cycle fatigue characteristics of typical flexural columns. A companion paper will present the results of variable amplitude tests to develop an analytical model of cumulative damage for rectangular reinforced concrete columns. Test observations indicate two potential failure modes: low cycle fatigue of the longitudinal reinforcing bars; and confinement failure due to rupture of the confining hoops. The former failure mode is associated with relatively large displacement amplitudes, while the latter is associated with a larger number of smaller amplitude cycles. A fatigue life expression is developed that can be used in damage-based seismic design of rectangular, flexural concrete columns.

scholarly journals Effect of Processing and Loading Conditions upon the Fatigue Behaviour of a Cf/Epoxy Laminate

2009 ◽  
Vol 18 (3) ◽  
pp. 096369350901800 ◽  
Author(s):  
Christos Koimtzoglou ◽  
Konstantinos G. Dassios ◽  
Costas Galiotis
Keyword(s):  
Fatigue Limit ◽  
Failure Modes ◽  
Matrix Material ◽  
High Stress ◽  
Fatigue Behaviour ◽  
Static Strength ◽  
Testing Conditions ◽  
The Matrix ◽  
The Mean ◽  
Loading Scheme

The current work reports on the tensile and fatigue behaviour of an autoclave-cured unidirectional carbon fibre reinforced epoxy-matrix laminate. The macromechanical properties of the composite are established under interrupted and uninterrupted, static and dynamic conditions at a maximum strain below the critical fatigue limit of the matrix material. The established S-N curve was used to calculate the endurance fatigue limit of the laminate as well as to record an increase in fatigue life of specimens tested at load levels lower than two standard deviations below the mean static strength of the material. The failure modes exhibited by the composite under all testing conditions were recorded and interpreted by means of the damage mechanisms that originate them. The results of interrupted testing showed that the combined effect of fatigue and residence at high stress levels for prolonged periods of time - conditions that simulate a realistic loading scheme- trigger premature fibre failure and thus specimen failure.

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