Rupture by impact-induced fatigue of a copper foil strip embedded in a multifunctional composite material

2021 ◽  
pp. 002199832199432
Author(s):  
Yacine Ouroua ◽  
Said Abdi ◽  
Imene Bachirbey
Keyword(s):  
Composite Material ◽  
Mechanical Characteristics ◽  
Glass Fibers ◽  
Energy Levels ◽  
Fatigue Tests ◽  
Repeated Impact ◽  
Aeronautical Industry ◽  
Repeated Impacts ◽  
Cracking Mode ◽  
The Impact

Multifunctional composite materials are highly sought-after by the aerospace and aeronautical industry but their performance depends on their ability to sustain various forms of damages, in particular damages due to repeated impacts. In this work we studied the mechanical behavior of a layered glass-epoxy composite with copper inserts subjected to fatigue under repeated impacts with different energy levels. Damage evolution as a function of impact energy was carefully monitored in order to determine the effect of the copper inserts on mechanical characteristics of the multifunctional composite, such as endurance and life. Results of repeated impact tests show that electric current interruption in the copper inserts occurs prior to the total perforation of the composite material, and after about 75% of the total number of impacts to failure. This is the case for the three energy levels considered in this study, [Formula: see text] = 2, 3 and 4 Joules. The epoxy resin was dissolved chemically in order to preserve the mechanical structure of the damaged copper inserts and the composite fibers for further inspection and analysis. Scanning electron microscopy (SEM) of the fractured copper inserts revealed interesting information on the nature of the damage, including information on plastic deformation, strain hardening, cracking mode, temperature increase during the impacts, and most importantly the glass fibers and their roles during the impact-fatigue tests.

scholarly journals Mechanical properties of composite material laminates reinforced by woven and non-woven glass fibers

2020 ◽  
Vol 175 ◽  
pp. 12005 ◽  
Author(s):  
Amer Karnoub ◽  
Hajian Huang ◽  
Imad Antypas
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Glass Fiber ◽  
Mechanical Characteristics ◽  
Polyester Resin ◽  
Mechanical Performance ◽  
Glass Fibers ◽  
Mechanical Tests ◽  
Impact Behavior ◽  
The Impact

The purpose of this work is to study the mechanical characteristics in 3-point bending and in traction; static; and the impact behavior of three specimens of laminates made of glass fiber and polyester resin non-woven and woven, with the aim of using them in the repair of boat hulls and enhancing their value in the naval industry. Three types of laminates were developed by contact molding. These different specimens of laminates made of woven, non-woven and combined glass fiber (woven and non-woven) were subjected to mechanical tests (traction and 3-point bending). Analysis of the results of the tests carried out on these three types of laminate shows that one specimen stands out and gives higher mechanical performance than the othertwo.

Experimental investigation on a fully thermoplastic composite subjected to repeated impacts

2019 ◽  
Vol 233 (19-20) ◽  
pp. 6985-7002
Author(s):  
S Boria ◽  
A Scattina ◽  
G Belingardi
Keyword(s):  
Composite Laminates ◽  
Mechanical Performance ◽  
Impact Damage ◽  
Energy Levels ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Low Velocity ◽  
Repeated Impacts ◽  
Structural Parts ◽  
The Impact

In the last years, the spread of composite laminates into the engineering sectors was observed; the main reason lies in higher values of strength/weight and stiffness/weight ratios with respect to conventional materials. Firstly, the attention was focused on fibres reinforced with thermosetting matrix. Then, the necessity to move towards low density and recyclable solutions has implied the development of composites made with thermoplastic matrix. Even if the first application of thermoplastic composites can be found into no structural parts, the replacement of metallic structural parts with such material in areas potentially subjected to impact has become worthy of investigation. Depending on the field of application and on the design geometry, in fact, some components can be subjected to repeated impacts at localized sites either during fabrication, activities of routine maintenance or during service conditions. When composite material was adopted, even though the impact damage associated to the single impact event can be slight, the accumulation of the damage over time may seriously weaken the mechanical performance of the structure. In this overview, the capability of energy absorption of a new composite completely made of thermoplastic material was investigated. This material was able to combine two conflicting requirements: the recyclability and the lightweight. In particular, repeated impacts at low velocity, on self-reinforced laminates made of polypropylene (PP), were conducted by experimental drop dart tests. Repeated impacts up to the perforation or up to 40 times were performed. In the analysis, three different energy levels and three different values of the laminate thicknesses were considered in order to analyse the damage behaviour under various experimental configurations. A visual observation of the impacted specimens was done, in order to evaluate the damage progression. Moreover, the trend of the peak force interchanged between specimen and dart and the evolution of both the absorbed energy and of the bending stiffness with the impacts number were studied. The results pointed out that the maximum load and the stiffness of the specimens tended to grow increasing the number of the repeated impacts. Such trend is opposite compared to the previous results obtained by other researchers using thermosetting composites.

Crack Propagation of CCT Foam Specimen under Impact Fatigue

2010 ◽  
Vol 118-120 ◽  
pp. 32-36 ◽  
Author(s):  
Jae Ung Cho ◽  
Li Yang Xie ◽  
Chong Du Cho ◽  
Sang Kyo Lee
Keyword(s):  
High Strain Rate ◽  
Impact Loading ◽  
High Strain ◽  
Nickel Foam ◽  
Fatigue Properties ◽  
Foam Material ◽  
Impact Fatigue ◽  
Repeated Impact ◽  
Repeated Impacts ◽  
The Impact

The objective of this study is to investigate the effect of the low or high strain rate on the impact fatigue properties of the nickel foam material and to understand the lifetime of this material which is subjected to the repeated impacts at different energy levels. Failures of foam materials under single and repeated impacts analogous to fatigue are essential to designers and users in military and aerospace structures. The material failure induced by repeated impact loading becomes a critical issue because of significant loss of stiffness and compressive strength in the foam material. Testing methods to study impact(that is, high strain rate) fatigue are quite numerous; no single standard testing procedure is defined for studying the impact fatigue property of a material. The increasing application of foam material in aerospace structures, owing to high specific stiffness and strength has attracted a great concern about the high sensitivity to impact damage introduced during manufacture or in service, and the effects of such damage on structural degradation. To investigate this issue, this study sets up an experimental procedure to determine the impact fatigue properties of nickel foam material. This study performs both experimental and numerical investigations to catch the impact fatigue behavior of nickel foam with open type. Design life and probability of failure or survival at specified life can be calculated so that the fatigue life of nickel core material subjected to repeated impact loading is predicted.

Experimental and Numerical Analysis of Repeated Impacts between Two Spheres

2014 ◽  
Vol 566 ◽  
pp. 250-255
Author(s):  
Hirofumi Minamoto ◽  
Robert Seifried ◽  
Peter Eberhard ◽  
Shozo Kawamura
Keyword(s):  
Full Detail ◽  
Repeated Impact ◽  
Velocity Change ◽  
Spherical Surfaces ◽  
Plastic Materials ◽  
Dynamic Material Properties ◽  
Repeated Impacts ◽  
The Impact ◽  
Method Analysis ◽  
Material Tests

The impact of spheres and bodies with spherical surfaces is frequently occurring in engineering applications. Only little research on repeated impacts of spheres is available and the variation of the COR (Coefficient of Restitution) due to repeated impacts is not fully understood yet. Further, the variation of the COR for impact repetition of visco-plastic materials, such as steel, has not been investigated in full detail yet. Therefore, the aim of this study is to investigate the behavior of steel spheres during repeated impact in detail in both, experiments and numerical simulations. In the experiments, two steel spheres are suspended like pendula, and the two spheres collide at the same position with the same initial velocity for every repeated impact. The COR is obtained from the velocity change of the spheres which is measured by LDVs (Laser Doppler Vibrometers) set at both sides of the spheres. The static and dynamic material properties are obtained from material tests and are incorporated into an FEM (Finite Element Method) analysis. The experimental results and the FEM results agree fairly well. It is observed that the COR increases toward to 1 by the repetition of impacts, indicating decreasing amount of plastic deformation in the successive impacts.

Static and fatigue behaviors of short glass fiber–reinforced polypropylene composites aged in a wet environment

2019 ◽  
Vol 53 (25) ◽  
pp. 3629-3647 ◽  
Author(s):  
Lilla Mansouri ◽  
Arezki Djebbar ◽  
Samir Khatir ◽  
Hafiz Tauqeer Ali ◽  
Amar Behtani ◽  
...  
Keyword(s):  
Composite Material ◽  
Glass Fibers ◽  
Fatigue Loading ◽  
Fatigue Tests ◽  
Distilled Water ◽  
Static Tests ◽  
Polypropylene Composites ◽  
Injection Process ◽  
Test Criteria ◽  
Short Glass

In this paper, a new experimental study of the bending static and fatigue behaviors of a composite material reinforced with 40% by mass of short glass fibers (type E) and polypropylene matrix is presented. The composite material is obtained in the form of plates by an injection process, which inevitably affects the distribution of the fibers and therefore the behavior of the material studied. To do this, several techniques are implemented on specimens by cutting them in transverse and longitudinal directions. The effect of aging in distilled water at 40℃ on the mechanical characteristics is studied under static and fatigue loading conditions. The static tests, three-point flexure up to failure, allow us to choose the levels of stress for the fatigue tests. The endurance curves as a function of the number of cycles are plotted by adapting the end-of-test criteria N5, N10, and N20, which represent a rigidity drop of 5%, 10%, and 20%, respectively. An interpretation of the Wöhler curve equations defined for the end-of-test criteria allows defining the kinetics of material damage. The results highlighted the influence of distilled water on the mechanical behavior and the lifetime of the material. We also perform macroscopic observations of fracture and microscopic facies in order to identify the damage mechanisms of the composite material.

A Smart Polymer Composite for Repeatedly Self-Healing Impact Damage in Fiber Reinforced Polymer (FRP) Vessels

2011 ◽  
Author(s):  
Jones Nji ◽  
Guoqiang Li
Keyword(s):  
Polymer Composite ◽  
Impact Damage ◽  
Glass Fibers ◽  
Shape Memory Polymer ◽  
Impact Resistance ◽  
Three Dimensional ◽  
Polymer Composite Material ◽  
Self Healing ◽  
Repeated Impact ◽  
The Impact

This paper investigated the impact properties of a novel polymer composite material with a potential to repeatedly self-heal impact damage in FRP vessels. The composite was fabricated by first dispersing copolyster thermoplastic particles in a shape memory polymer (SMP) matrix, and then reinforcing the material with three-dimensional (3D) woven glass fibers. Specimens of the reinforced composite with dimensions of 152 mm × 101 mm × 12.7 mm were produced by machining and divided into two groups (G1 and G2). G1 specimens were subjected to several impact/healing test cycles with 42 J of impact energy. G2 specimens were subjected to repeated impact test cycles with no healing at the same energy level. A third group of specimens without thermoplastic particles (G3), with identical dimensions as G2 was also produced and tested in a similar manner as G2 to evaluate the effects of thermoplastic particles on impact resistance. G2 specimens were perforated at the 40th impact while G3 specimens were perforated at the 27th impact. G1 specimens lasted an additional 9 rounds of impact to a total of 49 impacts compared to G2 specimens.

scholarly journals Strength Study of Sorption Composites Based on Microfine Glass Fibers

2020 ◽  
pp. 221-227
Author(s):  
В.К. Дубовый ◽  
Г.А. Суслов
Keyword(s):  
Composite Material ◽  
Organic Compounds ◽  
Glass Fibers ◽  
Aluminium Chloride ◽  
Polynuclear Complexes ◽  
Aluminium Sulfate ◽  
Low Concentrations ◽  
The Impact ◽  
Hydrolysis Of ◽  
Technological Strength

Исследуется влияние минерального и органического связующего на термостойкость и показатель разрушающего усилия композиционных сорбционных материалов на основе стеклянных волокон. Рассматриваемый материал используется для сорбции органических соединений при низких концентрациях. Изучение влияния на эти два показателя вызвано тем, что материал, описываемый в настоящей статье, требует определенной технологической прочности и должен выдерживать температуры 300 °С. Для достижения требуемых параметров для материала исследовались три типа связующего: 1. Полиядерные комплексы алюминия, полученные в результате гидролиза хлорида алюминия; 2. Полиядерные комплексы алюминия, полученные в результате гидролиза сульфата алюминия; 3. Сульфатная небеленая целлюлоза. По результатам исследования было выявлено наиболее подходящее связующее для сорбционного композиционного материала и определено оптимальное процентное содержание этого связующего. Discusses the influence of mineral and organic binders on the heat resistance and the index of the destructive force of composite sorption materials based on glass fibers. This material is used for sorption of organic compounds at low concentrations. Consideration of the impact on these two indicators is caused by the fact that the material described in this article requires a certain technological strength and must withstand temperatures of 300 °C. To achieve the required parameters for the material, three types of binder were studied: 1. Polynuclear complexes of aluminium, obtained by hydrolysis with aluminium chloride; 2. Polynuclear complexes of aluminium, obtained by hydrolysis of aluminium sulfate; 3. Sulfate unbleached cellulose. According to the results of the study, the most suitable binder for the sorption composite material was identified and the optimal percentage of this binder was determined.

Delamination-Crater Interaction in Damage of Glass/Epoxy Composite Plates Subjected to Impact Fatigue

2012 ◽  
Vol 498 ◽  
pp. 139-150 ◽  
Author(s):  
Said Mouhoubi ◽  
Krimo Azouaoui
Keyword(s):  
Energy Levels ◽  
Composite Plates ◽  
Fatigue Loading ◽  
Fatigue Tests ◽  
Woven Fabric ◽  
Impact Fatigue ◽  
Repeated Impact ◽  
Crater Size ◽  
Composite Glass ◽  
Impact Energies

The use of composite materials is increasing although their behavior under impact fatigue loading remains rather unknown. This study is to assess the evolution of damage, especially delamination and crater, in a composite Glass/Epoxy woven fabric, using repeated impact tests at low energy levels (<10J). Both types of damage that arise and grow within the material cannot be independent from each other. Our objective in this work is to establish the interaction between two damages (delamination and crater) on laminate damage, and understand the contribution of each of them in the different phases through which passes the composite before perforation. To do this, impact fatigue tests are carried out on composite plates and measures of the crater size (diameter and depth) and the size of the delaminated area (diagonals from a diamond shape) are collected for different numbers of impacts and impact energies. A question worth asking; can we foster one of these damages over the other? especially when we are interesting to the “structure applications”, where one "prefers" perforation to delamination (while completing correctly the function's intended to the structure), or “shielding applications”, where one "prefers" the delamination to perforation. Although the range of impact velocities is not the same, it is still interesting to consider the synergy between these two damages at low impact velocities, always in the case of “structure applications” and “shielding applications”.

Numerical Studies on Dynamic Behavior of Tubular Pipes Under Repeated Impacts

2020 ◽  
Author(s):  
Ling Zhu ◽  
Xiangui Wang ◽  
Kailing Guo ◽  
Bin Ma
Keyword(s):  
Numerical Simulation ◽  
Plastic Deformation ◽  
Dynamic Behavior ◽  
Deformation Energy ◽  
Repeated Impact ◽  
Numerical Studies ◽  
Repeated Impacts ◽  
The Impact ◽  
Local Dent ◽  
Good Agreement

Abstract The tubular pipes of Jacket platform may be frequently subjected to repeated impact loadings from vessels and dropped objects during the operation life, which may lead to serious damages to the platform. In this paper, the numerical studies on dynamic behavior of tubular pipe subjected to repeated impact loadings was performed. The deformation profile and permanent deflection in numerical simulation were compared with those in experiment, and good agreement was achieved. Besides, the mechanism of deformation accumulation and energy absorption were analyzed. Results showed that, the tubular pipe mainly produced transverse expanding and local dent, the global bending was very small. The permanent deflection at the middle of the pipe increased as the impact numbers increased, while the increment decreased. In addition, with the increase of impact number, the elastic deformation energy stored by the tubular pipe increased, and the plastic deformation energy decreased.

Composite material components damaged by impact loading: a methodology for the assessment of their residual elastic properties

2018 ◽  
Vol 1 (87) ◽  
pp. 18-24
Author(s):  
G. Belingardi ◽  
M.P. Cavatorta ◽  
D.S. Paolino
Keyword(s):  
Composite Material ◽  
Elastic Properties ◽  
Impact Loading ◽  
Composite Laminate ◽  
Impact Load ◽  
Damage Index ◽  
Composite Plates ◽  
Main Concern ◽  
Repeated Impact ◽  
The Impact

Purpose: Detection and evaluation of damage due to impact or fatigue loading in components made by composite materials is one of the main concern for automotive engineers. We focus on damage due to impact loading on long fibre, plastic matrix composite, as they represent one of the most interesting development solution for automotive components toward lightweight structure that in turn means reduction of fuel consumption and of Green House Gas emissions. Design/methodology/approach: An innovative simplified methodology is proposed, based on the impact and repeated impact behaviour of composite material, for the evaluation of the induced damage and of material residual elastic properties. The investigated composite laminate is made of eight twill-wave carbon fabrics impregnated with epoxy resin. The methodology consists of two phases: at first the identification of the impact response. Composite plates have been impacted at different energy levels and residual elastic properties measured through standard tensile tests. The relationship between impact energy and residual elastic properties is obtained. Then the exploration impact load is identified, large enough to give a well-defined picture of the suffered damage but soft enough to do not induce further damage in the composite laminate. Findings: This exploration impact test and the Damage Index (DI) value, as interpretation key, leads to a prediction of the local residual elastic properties in the damaged area. The proposed methodology has been validated on plate specimens. A strict correlation is found between the predicted and the actual residual elastic properties of the damaged composite plate. Practical implications: Subsequently it has been applied to a composite beam, with a omega shape transverse section, that can be considered as a demonstrator for a typical beam used in the car body frame. Originality/value: A selection on the following alternatives will be possible: a – don’t care the damage is not affecting the structure performance; b – repair is needed but will be sufficient; c – substitute the damaged component as soon as possible.

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