Rainwater effect on bearing strength of glass–epoxy laminated composite pinned joints

2016 ◽  
Vol 50 (30) ◽  
pp. 4269-4278 ◽  
Author(s):  
Onur Sayman ◽  
Ümran Esendemir
Keyword(s):  
Room Temperature ◽  
Failure Modes ◽  
Failure Load ◽  
Weight Ratio ◽  
Laminated Composite ◽  
Hole Diameter ◽  
Plastic Container ◽  
Specimen Width ◽  
Bearing Load ◽  
Pinned Joints

Composite materials are used in areas that have varying environmental conditions due to their advantages such as generally higher stiffness- and strength-to-weight ratio, and corrosion resistance compared to metallic alloys. This experimental study is carried out to investigate the bearing strengths and failure modes of woven glass–epoxy composite pinned joints subjected to rainwater. The specimens were immersed in rainwater in a closed plastic container indoors for 20 month periods at room temperature. The ratio of edge-distance-to-hole diameter (E/D) and the ratio of the specimen width-to-hole-diameter (W/D) were selected as parameters. Failure modes were determined by observing the failure regions on the specimens. Damage of immersed and unimmersed specimens was examined using scanning electron misroscopy for the same failure load. Experimental results showed that the bearing load values obtained from the specimens immersed in rainwater decreased in comparison to unimmersed specimens.

The Effects of Seawater Immersion on the Bearing Strength of Woven-Glass–Epoxy Prepreg Pin-Loaded Joints

2011 ◽  
Vol 21 (2) ◽  
pp. 153-170 ◽  
Author(s):  
AyŞe Öndürücü
Keyword(s):  
Failure Modes ◽  
Failure Load ◽  
Diameter Ratio ◽  
Hole Diameter ◽  
Natural Seawater ◽  
Bearing Strength ◽  
Specimen Width ◽  
Bearing Load ◽  
Mechanically Fastened ◽  
Ultimate Failure

This study considers the bearing strengths and failure modes of woven-glass–epoxy prepreg composite mechanically fastened joints. For the study, the specimens were immersed in natural seawater in the laboratory for over 1 year. The edge distance-to-hole diameter ( E/ D) ratio and the specimen width-to-hole-diameter ratio ( W/ D) were systematically altered during experiments. Failure modes were determined by observing the failure regions on the specimens. Damage progression in pin-loaded specimens prepared from woven-glass–epoxy prepreg was also examined using a scanning electron microscopy for three different percentages of ultimate failure load. According to the experimental investigation results, it was observed that the bearing load values obtained from the specimens immersed in seawater decreased considerably in comparison to unimmersed specimens.

scholarly journals Failure Strength of E-Glass/Epoxy Composite Pinned Joints: Effect of Geometry, Clamping Torque and Laminate Orientation

2007 ◽  
Vol 16 (3) ◽  
pp. 096369350701600 ◽  
Author(s):  
Yeliz Pekbey
Keyword(s):  
Composite Plate ◽  
Failure Modes ◽  
Failure Load ◽  
Epoxy Composite ◽  
Experimental Investigations ◽  
Failure Behavior ◽  
Displacement Curve ◽  
Failure Strength ◽  
Bearing Strength ◽  
Specimen Width

The experimental investigations described in this paper were conducted in order to study the strength and failure behavior of composite plate with pin-loaded conditions. The main objective of the present paper was to investigate the influence of certain factors on the strength of the pin-loaded in E-GLASS/EPOXY composite plate with different orientations such as [0/90/±30]s and [0/90/±60]s. These factors included the preload moment (M=0, 2 Nm), the ratio of the edge distance to the pin diameter ( E/ D), and the ratio of the specimen width to the pin diameter ( W/ D). The mechanical properties and failure strengths of E-GLASS/EPOXY composite were obtained with experimental measurements. Based on experiments, the effects of laminate orientation, and preload moment on joint strengths were systematically investigated. In addition, geometrical configurations of specimens were suitably varied in order to observe all possible failure modes. A total of 150 different pin-loaded composite plate specimens were tested under static loading conditions. The specimen tested exhibited different failure modes, consisting of bearing, net-tension and shear-out, depending on the geometry adopted. Guidelines for effective laminate orientations, geometrical configurations and preload moment for mechanically pin connected E-GLASS/EPOXY composite plate were specified based on ultimate bearing strength. From the experiments, it was also found that glass-epoxy with [0/90/±30]s yielded the highest bearing strengths. Bearing strengths reached when E/D and W/D ratios were equal or greater than 4 both [0/90/±30]s and [0/90/±60]s orientations. Besides, the experimental results showed that the load-displacement curve of specimen with M=0, had the lowest the failure strength. M=2Nm preload moment, had the maximum failure load.

scholarly journals Efficiency and Stiffness of the Single Lap Bolt Joints in Glass Epoxy Composites

2019 ◽  
Vol 69 (3) ◽  
pp. 280-289
Author(s):  
Jaspreet Singh ◽  
Kulwinder Singh ◽  
J. S. Saini
Keyword(s):  
Failure Modes ◽  
Failure Load ◽  
Characteristic Curve ◽  
Joint Stiffness ◽  
Failure Criteria ◽  
Hole Diameter ◽  
Outer Diameter ◽  
Joint Efficiency ◽  
Failure Loads ◽  
Joint Characteristic

The present work deals with the investigations on the joint efficiency and the joint stiffness of the single lap bolt joint made of two dimensional woven glass fibre reinforced composite materials. The effect of joint geometry, bolt pretension and washer has been determined on the bolt joint performance. To estimate the effect of geometric parameters; the edge-to-hole diameter (e/d) and width-to-hole diameter (w/d) ratios are varied from 3 to 4 and 3 to 5, respectively. To study the worst loading conditions; the bolt pre-tension is set to zero, whereas 5 Nm torque is applied to investigate the joint in fully clamped conditions. Two different sizes of washer i.e., the outer diameter of 12 mm and 16 mm have been studied to estimate the effect of the washer on failure load, joint stiffness, and joint efficiency. Progressive damage analysis has been performed on the single lap bolt joint. Characteristic curve method along with Tsai-Wu failure criteria has been used for the prediction of the failure loads and failure modes. The joint stiffness and the failure load of the joint are increased with the increase of w/d ratios. However, the joint efficiency was negatively influenced by w/d ratio.

Investigations to increase the failure load for joints in glass epoxy composites

2018 ◽  
Vol 233 (6) ◽  
pp. 2074-2090 ◽  
Author(s):  
Kulwinder Singh ◽  
JS Saini ◽  
H Bhunia ◽  
Jaspreet Singh
Keyword(s):  
Failure Modes ◽  
Failure Load ◽  
Failure Criteria ◽  
Hole Diameter ◽  
Glass Fiber Reinforced ◽  
Failure Loads ◽  
Ultimate Failure ◽  
Nanoclay Content ◽  
Woven Glass Fiber ◽  
Fiber Reinforced Laminates

The present work aims to increase failure loads of pin joints through nanofillers and metal inserts. Pin joints were prepared from woven glass fiber-reinforced laminates with nanoclay as filler material along with metal inserts fitted in holes. To investigate the effect of nanoclay content, 1–5 wt.% of nanoclay was mixed in epoxy. The increase in tensile strength up to 3 wt.% of nanoclay was observed which was due to increase in the specific surface area of the nanocomposite material. Dispersed nanoclay filler particles act as mechanical interlocking between fiber and epoxy matrix which creates a high friction coefficient. The optimal nanoclay content of 3 wt.% was finally used to prepare nanocomposite laminates. The geometric parameters, i.e. edge distance to hole diameter (E/D) ratio and width to hole diameter (W/D) ratio were varied from 2 to 5 and 3 to 6, respectively. Progressive damage analysis along with Hashin failure criteria was performed to predict failure loads and failure modes in pin joints, numerically. Metal inserts reduced the stress concentration around the hole and redistributed stresses at the pin/hole interface, which eventually increased the ultimate failure load of the joint.

Finite element analyses and experimental considerations of the deflection and failure behaviour of an asymmetric laminate composite bicycle handlebar

2002 ◽  
Vol 216 (4) ◽  
pp. 207-218 ◽  
Author(s):  
R R Chang
Keyword(s):  
Failure Modes ◽  
Laminate Composite ◽  
Failure Load ◽  
Laminated Composite ◽  
Experimental Results ◽  
Optimal Angle ◽  
Maximum Stiffness ◽  
Theoretical Predictions ◽  
Failure Loads ◽  
Experimental Approaches

The deformation and first-ply failure load of an asymmetric laminate composite bicycle handlebar have been studied via both theoretical and experimental approaches. The composite bicycle handlebar tube is fabricated with outer main fibre layers and inner reinforcing fibre layers and is designed to predicted first-ply failure loads. Optimal angle-ply orientations of antisymmetric [θ-θ…]-s laminated tubes designed for maximum stiffness were investigated. A number of laminated composite bicycle handlebars were fabricated and subjected to static transverse bend testing. The first-ply failure loads of laminated composite bicycle handlebars tubes were determined using acoustic emission (AE). The failure modes of the bicycle handlebars were studied, and experimental results were used to verify the theoretical predictions. The experimental results have been proved to be efficient and effective in the theoretical prediction of first-ply failure loads of laminated composite bicycle handlebars.

Characterization of Hot-Pressed Silicon Nitride Ceramics with Alkoxide-Derived Oxide Mixtures As the Sintering Aid

1992 ◽  
Vol 287 ◽  
Author(s):  
Y. Sato ◽  
C. Sakurai ◽  
M. Ueki ◽  
K. Sugita
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Weight Ratio ◽  
Sintering Aids ◽  
Sintering Aid ◽  
Oxide Powders ◽  
Nitride Ceramics ◽  
Final Weight ◽  
Alkoxide Method

ABSTRACTA homogeneous mixture of Y2O3, CeO2 and MgO with a final weight ratio of 3:1: 2 was prepared by the alkoxide method. The powder mixture was then added into Si3N4 powder in amounts ranging from 4 to 12 wt%, andconsolidated by hot-pressing. Microstructure and mechanical properties of the sintered bodies were determined and compared to those of materials prepared by the conventional route of mixing the oxide powders as sintering aids individually in essentially same composition. The β-fraction (modification ratio) in same composition was higher in thesintered bodies made through the alkoxide method than those made through the conventional one. The room temperature flexural strength was maximized with 6wt% addition of the alkoxide derived oxide, whereas, 12wt% addition of the total oxide was required to maximize the strength by conventional processing.

Predictions of first-ply failure load of laminated composite shafts

2003 ◽  
Vol 43 (2) ◽  
pp. 183-193 ◽  
Author(s):  
R. R. Chang ◽  
J. M. Chu
Keyword(s):  
Failure Load ◽  
Laminated Composite

scholarly journals Study of the Cryopreservation Conditions for seed Materials of Chartolepis intermedia Boiss.

2021 ◽  
Vol 38 ◽  
pp. 00046
Author(s):  
Margarita Ishmuratova ◽  
Saltanat Tleukenova ◽  
Alibek Ramasanov ◽  
Elena Gavrilkova ◽  
Dmitrii Ageev
Keyword(s):  
Seed Germination ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
Germination Rate ◽  
Plastic Container ◽  
In The Wild ◽  
First Time ◽  
Karaganda Region

For the first time, the depending of germination rate and energy of germination of Chartolepis intermedia seeds, collected in the wild of Karaganda region, from morphology of seeds and conditions of cryopreservation is investigated. The maximum results for viability are fixed for dark-colored average or large seeds. The best results are determined for variant of cryopreservation in plastic container with future defrosting at the room temperature. For the increasing parameters of seed germination we recommended to freeze Chartolepis intermedia seeds with using cryoprotector sucrose in concentration 20%. As the results of the study, we developed algorithm of cryopreservation of Chartolepis intermedia seeds in liquid nitrogen.

C-section Cold-Formed Steel as Structural Members in Housing Construction in the Philippines

2019 ◽  
Author(s):  
Bernardo A. Lejano
Keyword(s):  
Axial Compression ◽  
High Speed ◽  
Failure Modes ◽  
Weight Ratio ◽  
High Strength ◽  
The Philippines ◽  
Bending Test ◽  
Housing Construction ◽  
Distortional Buckling ◽  
Cold Formed Steel

<p>Getting good lumber for housing construction is becoming difficult in the Philippines due to existing partial log ban. Although, the use of reinforced concrete is still the most popular in construction, an emerging alternative is the use of cold-formed steel (CFS). It is gaining popularity because of its high strength-to- weight ratio. However, information about the structural performance of locally-produced cold-formed steel is almost nonexistent. Although, design provisions are stipulated in the local Code, these are based on formulas developed abroad, hence the need to investigate these cold-formed steel. This study focuses on the C-section cold-formed steel, which is the most popularly used. The objective is to verify its performance when subjected to axial compression and flexure, both experimentally and computationally. For the computational part, the formulas stipulated in the National Structural Code of the Philippines were followed. For the experimental part, the cold-formed steel members were subjected to compression loads and flexural loads. Aside from usual sensors, high-speed cameras were used to capture the failure modes. For axial compression test, 80 specimens with different lengths and thicknesses were tested. For flexure, 24 specimens of back-to-back C-sections were subjected to 4-point bending test. Results showed the predicted strengths were well below the experimental values. In design, this means the use of Code-based formulas is conservative. Failure modes observed were torsional buckling and distortional buckling. Comparison of failure modes between experiment and computation shows 70% agreement for compression and 75% for flexure. Finite element method calculations were also done and were compared with experimental results.</p>

scholarly journals A simplified monitoring model for PMSM servoactuator prognostics

2019 ◽  
Vol 304 ◽  
pp. 04013 ◽  
Author(s):  
Pier Carlo Berri ◽  
Matteo D.L. Dalla Vedova ◽  
Paolo Maggiore ◽  
Francesco Viglione
Keyword(s):  
Failure Modes ◽  
Position Control ◽  
Health Management ◽  
Risk Mitigation ◽  
Fuel Efficiency ◽  
Computational Cost ◽  
Weight Ratio ◽  
Safety Critical ◽  
Aircraft Systems ◽  
Fidelity Model

Electromechanical actuators (EMAs) based on Permanent Magnet Synchronous Motors (PMSMs) are currently employed on various aircraft systems, and are becoming more and more widespread in safety critical applications. Compared to other electrical machines, PMSM offer a high power to weight ratio and low cogging: this makes them suited for position control and actuation tasks. EMAs offer several advantages over hydraulic servoactuators, in terms of modularity, mechanical simplicity, overall weight and fuel efficiency. At the same time, their basic reliability is inherently lower compared to hydraulic actuators. Then, the use of EMAs for safety critical aircraft systems requires the adoption of risk mitigation techniques to counter this issue. In this framework, diagnostic and prognostic strategies can be used for the system health management, to monitor its behaviour in search of the early signs of the most common or dangerous failure modes. We propose a low fidelity model of a PMSM based EMA, intended for model-based diagnostic and prognostic monitoring. The model features low computational cost, allowing the execution in nearly real-time, combined with suitable accuracy in the simulation of faulty system operations. This simplified emulator is validated by comparing its behaviour to a higher fidelity model, employed as a simulated test bench.

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