Numerical Study on Buckling Resistance of Uniaxially Compressed Laminates Containing V-Shaped Edge Notch

2021 ◽  
Vol 41 ◽  
pp. 27-41
Author(s):  
Nikhil Aditya ◽  
Jyoti Vimal
Keyword(s):  
Composite Laminates ◽  
Numerical Study ◽  
Weight Ratio ◽  
Considerable Effect ◽  
Notch Radius ◽  
Notch Angle ◽  
Buckling Strength ◽  
End Conditions ◽  
Edge Notch ◽  
The Impact

The purpose of this study is to investigate the impact of a V-shaped cutout on the buckling strength of E-glass epoxy composite laminates. In aircraft components, cutouts are more often used for inspection, ventilation, access to critical areas, fitting a particular component, and increasing the strength to weight ratio of the structure. In this paper, symmetric and antisymmetric laminates of E-Glass/Epoxy unidirectional are used and the effect of notch parameters such as notch radius(r), depth of the notch(h), and notch angle(α) is observed under monoaxial compression. Effects of end conditions and plate aspect ratio(l/b) are analyzed. It is observed that the notch radius does not have a considerable effect on buckling strength but the notch angle after 90⁰ shows a good dip in buckling loads as compared to 30⁰,45⁰, and 60⁰. Depth of notch and end conditions creates a considerable loss in buckling strength. As the h/b ratio is increased, the drop in buckling strength becomes significant. Clamped -pinned end condition of the plate gives a lower value of load multiplier as compared to clamped -clamped. As we increase the l/b ratio of the plate, buckling of the plate becomes easier. The position of the notch (a) also affects buckling strength which is maximum for a/l=0.25 and minimum for a/l=0.5.

Numerical Investigation of a Stiffened Panel Subjected to Low Velocity Impacts

2015 ◽  
Vol 665 ◽  
pp. 277-280 ◽  
Author(s):  
Aniello Riccio ◽  
S. Saputo ◽  
A. Sellitto ◽  
A. Raimondo ◽  
R. Ricchiuto
Keyword(s):  
Numerical Investigation ◽  
Composite Laminates ◽  
Mechanical Response ◽  
Numerical Study ◽  
Fem Analysis ◽  
Matrix Cracking ◽  
Stiffened Panel ◽  
Low Velocity ◽  
Formation And Evolution ◽  
The Impact

The investigation of fiber-reinforced composite laminates mechanical response under impact loads can be very difficult due to simultaneous failure phenomena. Indeed, as a consequence of low velocity impacts, intra-laminar damage as fiber and matrix cracking and inter-laminar damage, such as delamination, often take place concurrently, leading to significant reductions in terms of strength and stability for composite structure. In this paper a numerical study is proposed which, by means of non-linear explicit FEM analysis, aims to completely characterize the composite reinforced laminates damage under low velocity impacts. The numerical investigation allowed to obtain an exhaustive insight on the different phases of the impact event considering the damage formation and evolution. Five different impact locations with the same impact energy are taken into account to investigate the influence on the onset and growth of damage.

A numerical study of the influence of Z-pin parameters on the elastic properties of laminates

2020 ◽  
pp. 096739112097008
Author(s):  
Mengjia Li ◽  
Puhui Chen
Keyword(s):  
Elastic Properties ◽  
Composite Laminates ◽  
Numerical Study ◽  
Element Model ◽  
Fe Model ◽  
Insertion Angle ◽  
Benchmark Tests ◽  
Parametric Analyses ◽  
Longitudinal Modulus ◽  
The Impact

A finite element model with periodic boundary conditions was developed to investigate the influence of different Z-pin parameters including diameter, spacing, and insertion angle of Z-pin on the elastic properties of composite laminates. Benchmark tests were carried out to verify the FE model and a series of parametric analyses were subsequently performed. In general, all the elastic moduli, excluding the through-thickness modulus ( Ez), decreased while Ez increased nonlinearly with increasing Z-pin diameter and decreasing spacing. The reduction of Ey (transverse modulus) was approximately 40% of that of Ex (longitudinal modulus), while the reduction of Gxy is similar to that of Ex. Besides, Gxz and Gyz were reduced by approximately half of the reduction of Gxy. Although the impact of insertion angle was obvious on Ez, it was negligible on the other five moduli.

scholarly journals Mechanical Characterization of TiO2 nanoparticles based on Glass Fiber Reinforced Polymer Composite

2021 ◽  
Vol 1206 (1) ◽  
pp. 012006
Author(s):  
Abhishek Singh ◽  
S. C. Jayswal
Keyword(s):  
Glass Fiber ◽  
Polymer Composite ◽  
Composite Laminates ◽  
Weight Ratio ◽  
High Strength ◽  
Bending Stiffness ◽  
Flexural Properties ◽  
Nano Composite ◽  
Set Up ◽  
The Impact

Abstract Nanotechnology has become the best truly developing innovation in the field of engineering science. Numerous examinations have been completed by different exploration researchers in the prior many years. In my examination work research, the impact of cross breed E-glass built up fiber with epoxy Nano composite. The Nano composite covers overlays were set up by hand layup procedures by shifting layers of Titanium Dioxide (TiO2) nanoparticles of 0.6% individually. The nano added substances are utilized to improve the strength from destroy opposition, hardness of the polymer composite and high strength to weight ratio. The Nano composite laminates this prepared are characterized by the compression and flexural test. The flexural properties of the glass fiber built up plastic improved with expansion of nanoTiO2 filler particles. At 0.6 wt% of TiO2 and having 12 layers the force at yield is 327.99N and bending stiffness 63.11 N/mm and in 9 layers force at yield is 149.06 and bending stiffness 36.22 N/mm. True interfacial bonding b/w the fiber and epoxy turned into the primary motive for reaching higher flexural properties.

scholarly journals The influence of the inter-ply hybridisation on the mechanical performance of composite laminates: Experimental and numerical analysis

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110232
Author(s):  
Hussein Dalfi ◽  
Anwer J Al-Obaidi ◽  
Hussein Razaq
Keyword(s):  
Elastic Constants ◽  
Hybrid Composite ◽  
Composite Laminates ◽  
Failure Modes ◽  
Mechanical Response ◽  
Mechanical Performance ◽  
Numerical Study ◽  
Geometric Model ◽  
Woven Fabric ◽  
The Impact

Recently, high tensile fibres composite laminates (i.e. glass composite laminates) have been widely used in the civil and military applications due to their superior properties such as lightweight, fatigue and corrosion resistance compared to metals. Nevertheless, their brittle fracture behaviour is a real downside for many sectors. In the present study, the impact of the hybridisation of Kevlar woven layers with glass woven layers on the reducing the strain failure problem in pure glass woven laminates is investigated. In this work, multi-layers Kevlar-glass with different stacking sequences have been used to prepare the hybrid composite laminates using vacuum–assisted resin moulding method. The influence of the layers hybridisation on the mechanical performance of composites laminates was investigated using tensile strength tests. Furthermore, finite element analysis is performed to analyse the mechanical response of the hybrid composite laminates using Abaqus software. The elastic constants of woven fabric layers in the numerical study were predicted through geometric model based on the textile geometry and analytical method in order to assert accuracy of the predicted elastic constants. The experimental results showed that the hybrid composite laminates tend to fail more slowly than glass woven laminates, which illustrates low strain to failure. In the theoretical part of the study, it was found that the proposal model can be useful to capture the mechanical behaviour and the damage failure modes of hybrid laminates. Thus, the catastrophic failure can be avoided in these laminates.

scholarly journals Impact Strength of Glass/Kevlar Fiber Hybrid Composites with Various Stacking Sequences and Impact Energies

2019 ◽  
Vol 8 (6) ◽  
pp. 4286-4293
Keyword(s):  
Impact Strength ◽  
Impact Loading ◽  
Hybrid Composite ◽  
Composite Laminates ◽  
Hybrid Composites ◽  
Impact Resistance ◽  
Weight Ratio ◽  
Stacking Sequence ◽  
Kevlar Fiber ◽  
The Impact

Hybrid composites have been considered as modern materials for many engineering applications, yet there is still a major concern on the influence of stacking sequence configuration in hybrid composite laminates especially under impact loading. Therefore, the focus of this paper is to determine the optimized stacking sequence of glass/Kevlar fiber hybrid composite laminates under impact loading. Hybrid composite laminates were fabricated using vacuum bagging method with four different stacking sequences known as H1, H2, H3 and H4. Low velocity drop weight impact test (ASTM D7136) was conducted using a hemispherical nose impactor diameter of 12 mm with a mass of 6 kg at impact energy levels of 10 J, 20 J, 30 J, and 40 J. From the results obtained, H3 specimen which has a stacking sequence of glass fiber in the exterior part with Kevlar fiber in the interior part was concluded as the optimized stacking sequence with better impact resistance properties. H3 specimen recorded a higher value in peak load, maximum initiation energy, high impact strength, high strength to weight ratio and high total energy absorbed to weight ratio. In addition, it was observed that H3 specimen has less damaged area compared to H1, H2, and H4 specimens. This study contributes knowledge on the impact resistance properties of hybrid composite laminates which will be much useful for material selection and product development.

Influence of Ply Stacking Sequences on the Impact Response of Carbon Fibre Reinforced Polymer Composite Laminates

2019 ◽  
Author(s):  
Kristian Gjerrestad Andersen ◽  
Gbanaibolou Jombo ◽  
Sikiru Oluwarotimi Ismail ◽  
Segun Adeyemi ◽  
Rajini N ◽  
...  
Keyword(s):  
Carbon Fibre ◽  
Polymer Composite ◽  
Composite Laminates ◽  
Impact Response ◽  
Reinforced Polymer ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
The Impact

scholarly journals Model of thermal buoyancy in cavity-ventilated roof constructions

2021 ◽  
pp. 174425912098418
Author(s):  
Toivo Säwén ◽  
Martina Stockhaus ◽  
Carl-Eric Hagentoft ◽  
Nora Schjøth Bunkholt ◽  
Paula Wahlgren
Keyword(s):  
Analytical Model ◽  
Flow Rate ◽  
Numerical Study ◽  
Air Flow ◽  
Wind Pressure ◽  
Air Flow Rate ◽  
Test Set ◽  
Air Cavity ◽  
Thermal Buoyancy ◽  
The Impact

Timber roof constructions are commonly ventilated through an air cavity beneath the roof sheathing in order to remove heat and moisture from the construction. The driving forces for this ventilation are wind pressure and thermal buoyancy. The wind driven ventilation has been studied extensively, while models for predicting buoyant flow are less developed. In the present study, a novel analytical model is presented to predict the air flow caused by thermal buoyancy in a ventilated roof construction. The model provides means to calculate the cavity Rayleigh number for the roof construction, which is then correlated with the air flow rate. The model predictions are compared to the results of an experimental and a numerical study examining the effect of different cavity designs and inclinations on the air flow rate in a ventilated roof subjected to varying heat loads. Over 80 different test set-ups, the analytical model was found to replicate both experimental and numerical results within an acceptable margin. The effect of an increased total roof height, air cavity height and solar heat load for a given construction is an increased air flow rate through the air cavity. On average, the analytical model predicts a 3% higher air flow rate than found in the numerical study, and a 20% lower air flow rate than found in the experimental study, for comparable test set-ups. The model provided can be used to predict the air flow rate in cavities of varying design, and to quantify the impact of suggested roof design changes. The result can be used as a basis for estimating the moisture safety of a roof construction.

scholarly journals Numerical Simulation of the Impact of the Heat Source Position on Melting of a Nano-Enhanced Phase Change Material

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1425
Author(s):  
Tarek Bouzennada ◽  
Farid Mechighel ◽  
Kaouther Ghachem ◽  
Lioua Kolsi
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Numerical Study ◽  
Melting Rate ◽  
Heat Transfer Fluid ◽  
Commercial Code ◽  
Tube Position ◽  
The Impact ◽  
Change Material

A 2D-symmetric numerical study of a new design of Nano-Enhanced Phase change material (NEPCM)-filled enclosure is presented in this paper. The enclosure is equipped with an inner tube allowing the circulation of the heat transfer fluid (HTF); n-Octadecane is chosen as phase change material (PCM). Comsol-Multiphysics commercial code was used to solve the governing equations. This study has been performed to examine the heat distribution and melting rate under the influence of the inner-tube position and the concentration of the nanoparticles dispersed in the PCM. The inner tube was located at three different vertical positions and the nanoparticle concentration was varied from 0 to 0.06. The results revealed that both heat transfer/melting rates are improved when the inner tube is located at the bottom region of the enclosure and by increasing the concentration of the nanoparticles. The addition of the nanoparticles enhances the heat transfer due to the considerable increase in conductivity. On the other hand, by placing the tube in the bottom area of the enclosure, the liquid PCM gets a wider space, allowing the intensification of the natural convection.

OPTIMAL REINSURANCE FROM THE VIEWPOINTS OF BOTH AN INSURER AND A REINSURER UNDER THE CVAR RISK MEASURE AND VAJDA CONDITION

2021 ◽  
pp. 1-29
Author(s):  
Yanhong Chen
Keyword(s):  
Loss Function ◽  
Value At Risk ◽  
Numerical Study ◽  
Risk Measure ◽  
Convex Combination ◽  
Weighting Factor ◽  
Loss Functions ◽  
Conditional Value At Risk ◽  
Optimal Reinsurance ◽  
The Impact

ABSTRACT In this paper, we study the optimal reinsurance contracts that minimize the convex combination of the Conditional Value-at-Risk (CVaR) of the insurer’s loss and the reinsurer’s loss over the class of ceded loss functions such that the retained loss function is increasing and the ceded loss function satisfies Vajda condition. Among a general class of reinsurance premium principles that satisfy the properties of risk loading and convex order preserving, the optimal solutions are obtained. Our results show that the optimal ceded loss functions are in the form of five interconnected segments for general reinsurance premium principles, and they can be further simplified to four interconnected segments if more properties are added to reinsurance premium principles. Finally, we derive optimal parameters for the expected value premium principle and give a numerical study to analyze the impact of the weighting factor on the optimal reinsurance.

scholarly journals A numerical study of the impact perforation of sandwich panels with graded hollow sphere cores

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110094
Author(s):  
Ibrahim Elnasri ◽  
Han Zhao
Keyword(s):  
Boundary Conditions ◽  
Hollow Sphere ◽  
Sandwich Panel ◽  
Numerical Study ◽  
Sandwich Panels ◽  
Hopkinson Bar ◽  
Core Density ◽  
The Core ◽  
The Impact ◽  
Force Displacement

In this study, we numerically investigate the impact perforation of sandwich panels made of 0.8 mm 2024-T3 aluminum alloy skin sheets and graded polymeric hollow sphere cores with four different gradient profiles. A suitable numerical model was conducted using the LS-DYNA code, calibrated with an inverse perforation test, instrumented with a Hopkinson bar, and validated using experimental data from the literature. Moreover, the effects of quasi-static loading, landing rates, and boundary conditions on the perforation resistance of the studied graded core sandwich panels were discussed. The simulation results showed that the piercing force–displacement response of the graded core sandwich panels is affected by the core density gradient profiles. Besides, the energy absorption capability can be effectively enhanced by modifying the arrangement of the core layers with unclumping boundary conditions in the graded core sandwich panel, which is rather too hard to achieve with clumping boundary conditions.

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