Influence of Hygrothermal Environmental Conditions on the Vibratory Responses of Glass Polyester Composite Plate Impacted by a Steel Projectile

2017 ◽  
Vol 28 ◽  
pp. 8-20
Author(s):  
Amine Bakhti ◽  
Farouk Benallel Boukhoulda
Keyword(s):  
Contact Force ◽  
Energy Levels ◽  
Composite Plates ◽  
Mechanical Responses ◽  
System A ◽  
Resonance Frequencies ◽  
Polyester Composite ◽  
The Impact ◽  
Aged Composite

The objective of the present work is an analysis of vibratory responses due to the impact of projectile in steel against a glass/polyester composite material under hygrothermal conditions with different energy levels. In the first part of this study, by means of a data acquisition system, a signal processing analysis of the contact force and acceleration of the projectile is carried out in order to deduce the oscillations of the responses. These are generated by the vibrations induced by the contact between the plate and the impactor. The analysis of the vibrations by the calculation of the Fast Fourier Transform (FFT) applied to the oscillations of the contact force allows to defining the resonance frequencies of the plate for the different energy levels. The measure of the Frequency Response Functions (FRF) from the obtained responses allows the determination of the damping of the impacted composite material.In the second part of this study highlights quantitatively and puts into evidence the influence of hygrothermal conditions on the mechanical responses such as contact force, acceleration, frequency and damping of aged and non-aged composite plates.

Determination of Damage Levels of Composite Plates after Low Velocity Impacts Using Acoustic Emission

2006 ◽  
Vol 13-14 ◽  
pp. 253-258 ◽  
Author(s):  
Timothy P. Bradshaw ◽  
Mark J. Eaton ◽  
Rhys Pullin ◽  
S.L. Evans ◽  
C.A. Featherston
Keyword(s):  
Impact Damage ◽  
Composite Plates ◽  
Low Velocity Impact ◽  
Test Rig ◽  
Low Velocity ◽  
Energy Data ◽  
Absolute Energy ◽  
The Impact ◽  
Super Glue

Eight composite plates 400x410x2.15mm were fabricated from carbon/epoxy in ((0,90)4)s lay-up. To ensure there was no damage in the plates prior to the impact investigations the plates were C-scanned. A drop test rig was used to apply a low velocity impact to the undamaged plates. A rebound mechanism was employed to prevent secondary impacts. AE sensors were selected for frequency and size due to the limited space on the test rig. Super glue was used both as a couplant and also to secure the sensors in position. During the impact wave streaming, time driven data and hit driven data were used to record the impact simultaneously. One test was conducted on each sample with two impacts completed at 5J, 6J, 8J and 10J (total of 8 samples). The impacts were designed to allow only slight visible impact damage to be formed. After completion of the impact investigation the plates were C-scanned to determine the area of debonded material. Analysis of the data showed the complete record of the impact event from the wave streaming, while the hit driven and time driven absolute energy data provided increasing correlations with the area of composite damaged.

The flexural behaviors of the impacted composite single-lap adhesive joints

2015 ◽  
Vol 22 (5) ◽  
Author(s):  
Emin Ergun ◽  
Hasan Çallioğlu
Keyword(s):  
Experimental Study ◽  
Impact Energy ◽  
Energy Levels ◽  
Composite Plates ◽  
Lap Joints ◽  
Adhesive Joints ◽  
Single Lap Joints ◽  
Impact Tests ◽  
Impact Energies ◽  
The Impact

AbstractThis experimental study deals with the flexural behaviors of composite single-lap adhesive joints after impact tests. Increasing impact energies are applied at the center of the composite plates having three different overlap lengths. It is shown that the overlap lengths and impact energy levels affect considerably the impact responses of the composite single-lap joints. It is also shown that the bending stiffness of the composite increases with increasing overlap length. For this reason, after the impact tests, how these effects influence the flexural behaviors of the impacted composite lap joints was also investigated. The flexural loads of the impacted and non-impacted composite single-lap joints were determined and compared with each other. It is shown that the residual flexural loads after impact increase with increasing overlap lengths but decrease with increasing impact energy.

Using Modal Analysis and Optimization to Determine Elastic Constants of Thick Composite Plates

2009 ◽  
Vol 419-420 ◽  
pp. 473-476 ◽  
Author(s):  
Yu Hua Lin ◽  
Chia Lung Chang
Keyword(s):  
Objective Function ◽  
Elastic Constants ◽  
Simulated Annealing Algorithm ◽  
Composite Plates ◽  
Free Edge ◽  
Optimization Techniques ◽  
Genetic Simulated Annealing Algorithm ◽  
Design Variables ◽  
Resonance Frequencies

This paper presents an inverse method to derive the elastic constants of thick composite plates from the resonance frequencies of a free-edge test specimen based on modal vibration test. A mixed numerical experimental identification procedure is used for this purpose. The sum of the squared differences between the experimental frequencies and analytical frequencies from finite element method is chosen as the objective function. The optimization techniques, Hybrid Genetic /Simulated Annealing algorithm, have been applied to determine the elastic constants. As the objective function reaches its minimum, its corresponding design variables are the elastic constants of the material. The present method is applied to determine the elastic constants of AS4/PEKK material. The results indicate that different stacking sequences and numbers of frequencies have effects on the determination of elastic constants of the materials.

The Effect of the Boundary Conditions on the Impact Behaviors of Stitched Composite Lap Joints

2016 ◽  
Vol 25 (1) ◽  
pp. 096369351602500
Author(s):  
Emin Ergun ◽  
Ismail Gökkaya
Keyword(s):  
Boundary Conditions ◽  
Energy Levels ◽  
Composite Plates ◽  
Lap Joints ◽  
Transverse Impact ◽  
Adhesively Bonded ◽  
Bonded Composite ◽  
Infusion Method ◽  
Impact Characteristics ◽  
The Impact

In this study, transverse impact behaviors of stitch adhesively bonded composite lap joints having three different overlap lengths (20, 40 and 60 mm) at different energy levels are investigated. The effects of the boundary conditions (clamped-clamped and clamped-free) and three different span lengths (40, 60 and 80 mm) have been determined. The impacts energies are varied in a range from 5 J to 20 J. Vacuum assisted resin infusion method (VARIM) is used to manufacture composite plates. It is shown that the boundary conditions and span lengths affect considerably the impact responses of the stitch composites lap joints. The important impact characteristics of the composite lap joints are compared with each other and discussed. The observed damages of the composite lap joints are presented.

scholarly journals The g factor in a light two-body atomic system: a determination of fundamental constants to test QED

2002 ◽  
Vol 80 (11) ◽  
pp. 1305-1312 ◽  
Author(s):  
S G Karshenboim ◽  
V G Ivanov
Keyword(s):  
Atomic System ◽  
Magnetic Moments ◽  
Energy Levels ◽  
Homogeneous Magnetic Field ◽  
Fundamental Constants ◽  
Atomic Systems ◽  
System A ◽  
New Generation ◽  
G Factors

The energy levels of a two-body atomic system in an external homogeneous magnetic field can be presented in terms of the magnetic moments of their components, however, those magnetic moments being related to bound particles differ from their free values. The study of bound g-factors in simple atomic systems are now of interest because of recent progress in experiments on medium-Z ions and of a new generation of muonium experiments possible with upcoming intensive muon sources. We consider bound corrections to the g factors in several atomic systems, for which experimental data are available in the literature: hydrogen, helium-3 ion, muonium, hydrogen-like ions with spinless nuclei with medium Z. PACS Nos.: 12.20Fv, 31.30Jv, 32.10Hq

scholarly journals Experimental and Numerical Analysis of Low-Velocity Impact of Carbon Fibre-Based Non-Crimp Fabric Reinforced Thermoplastic Composites

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3642
Author(s):  
Muhammad Ameerul Atrash Mohsin ◽  
Lorenzo Iannucci ◽  
Emile S. Greenhalgh
Keyword(s):  
Finite Element ◽  
Carbon Fibre ◽  
Energy Levels ◽  
Composite Plates ◽  
Low Velocity Impact ◽  
Thermoplastic Composites ◽  
Low Velocity ◽  
Velocity Impact ◽  
Extent Of Damage ◽  
The Impact

There has been a lot of interest in understanding the low-velocity impact (LVI) response of thermoplastic composites. However, little research has focussed on studying the impact behaviour of non-crimp fabric (NCF)-based fibre reinforced thermoplastic composites. The purpose of this study was to evaluate the LVI responses of two types of non-crimp fabric (NCF) carbon fibre reinforced thermoplastic laminated composites that have been considered attractive in the automotive and aerospace industry: (i) T700/polyamide 6.6 (PA6.6) and (ii) T700/polyphenylene sulphide (PPS). Each carbon/thermoplastic type was impacted at three different energy levels (40, 100 and 160 J), which were determined to achieve three degrees of penetrability, i.e., no penetration, partial penetration and full penetration, respectively. Two distinct non-destructive evaluation (NDE) techniques ((i) ultrasonic C-scanning and (ii) X-ray tomography) were used to assess the extent of damage after impact. The laminated composite plates were subjected to an out-of-plane, localised impact using an INSTRON® drop-weight tower with a hemispherical impactor measuring 16 mm in diameter. The time histories of force, deflection and velocity are reported and discussed. A nonlinear finite element model of the LVI phenomenon was developed using a finite element (FE) solver LS-DYNA® and validated against the experimental observations. The extent of damage observed and level of impact energy absorption calculated on both the experiment and FE analysis are compared and discussed.

'Attack of the Drones' Exploration of Sound Power Levels Emitted and the Impact Drone's could have upon Rural Areas, Roxwell, Essex, UK

2021 ◽  
Vol 263 (5) ◽  
pp. 1462-1470
Author(s):  
Josephine Nixon ◽  
Stephen Dance
Keyword(s):  
Acoustic Emission ◽  
Rural Areas ◽  
Sound Pressure ◽  
Energy Levels ◽  
Rotor Blades ◽  
Rural Setting ◽  
Sound Power ◽  
Noise Sources ◽  
The Impact

This study considers the acoustic emission from a DJi Phantom 4 commercial drone using different rotor blades. Measurements were taken from a hovering drone with four commercial product blade configurations. Measurements were taken in accordance with (BS) EN ISO 3745: 2009 'Acoustics - Determination of sound power levels and sound energy levels of noise sources using sound pressure - Precision methods for anechoic rooms and hemi-anechoic rooms'. The aim of the project was to consider the sound characteristics emitted, specifically tonality and to determine the distance a drone could be heard from, with the different blade configurations, in a rural setting. By considering the different blade configurations within a rural setting, the role drones have within society is considered.

An Assesment of the Impacted Composite Single-Lap Adhesive Joints

2015 ◽  
Vol 31 (4) ◽  
pp. 433-439
Author(s):  
H. Çallioğlu ◽  
E. Ergun
Keyword(s):  
Experimental Study ◽  
Impact Energy ◽  
Energy Levels ◽  
Composite Plates ◽  
Lap Joints ◽  
Adhesive Joints ◽  
Single Lap Joints ◽  
Impact Energies ◽  
The Impact ◽  
Energy Profiling

AbstractThe aim of this experimental study is to investigate impact behaviors of the composite single-lap adhesive joints. The increasing impact energies, which are ranged from approximately 5 J to 30 J, are performed at the center of the composite plates having three different overlap lengths. It is shown that the overlap lengths and impact energy levels affect considerably the impact responses of the composite single lap joints. It is also shown that the bending stiffness of the composite increases by increase in the overlap length. An energy profiling method (EPM) is used to identify the penetration and perforation thresholds of composite lap joints. The damaged composite plates are visually inspected.

Impact Dynamic Analysis of Elastic Multibody in an Spring Actuated System

2005 ◽  
Author(s):  
Won-Sun Chung ◽  
Kil-Young Ahn ◽  
Woo-Jin Park ◽  
Il-Sung Oh
Keyword(s):  
Contact Force ◽  
Optimization Technique ◽  
Nonlinear Damping ◽  
Force Model ◽  
Electric Circuits ◽  
System A ◽  
Contact Force Model ◽  
Switch Mechanism ◽  
Free Drop ◽  
The Impact

In this paper, the contact force between two colliding bodies is modeled by using Hertz’s force-displacement law and nonlinear damping function. In order to verify the appropriateness of the proposed contact force model, the free drop type impact test is carried out for different impact velocities and different materials of the impacting body, such as rubber, plastic and steel. The drop type impact experiment are installed to measure the velocity before impact more accurately, which verify the characteristics of contact force model. The parameters of the contact force model are estimated using the optimization technique. Finally the estimated parameters are used to predict the impact force between two colliding bodies in opening action of the spring actuated linkage system, a kind of switch mechanism for switching electric circuits.

Impact response of composite plates manufactured with stitch-bonded non-crimp glass fiber fabrics

2014 ◽  
Vol 21 (1) ◽  
pp. 111-120 ◽  
Author(s):  
Numan Behlül Bektaş ◽  
İnan Ağır
Keyword(s):  
Glass Fiber ◽  
Matrix Material ◽  
Testing Machine ◽  
Composite Plates ◽  
Impact Testing ◽  
Impact Response ◽  
Damage Initiation ◽  
Polyester Composite ◽  
Impact Energies ◽  
The Impact

AbstractThis experimental study deals with the impact response of composite plates manufactured with stitch-bonded non-crimp glass fiber fabrics. Three kinds of fabrics – biaxial, triaxial, and quadraxial – are used as reinforcing material. Polyester resin is used as a matrix material in the composition of composite plates. An instrumented drop weight impact testing machine, Instron-Dynatup 9250 HV, is used for impact testing. Impact tests are performed under various impact energies, ranging from damage initiation to final perforation. An energy profiling method, showing the relation between impact energy and absorbed energy, was used together with load-deflection curves to determine the penetration and perforation thresholds of those composites. The failure processes of damaged specimens for different impact energies were evaluated by comparing load-deflection curves and images of damaged samples taken from the impacted and non-impacted sides. All types of composites have obvious penetration and perforation thresholds. The perforation threshold of triaxial/polyester composite is approximately 27% and 22% higher than that of the quadraxial and biaxial/polyester composites, respectively.

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