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

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.

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

Journal of Composite Materials ◽

10.1177/0021998321994327 ◽

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.

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Effect of Natural Ageing on the Physical Properties of Polypropylene Composites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1001.141 ◽

2014 ◽

Vol 1001 ◽

pp. 141-148 ◽

Cited By ~ 3

Author(s):

Aneta Krzyżak ◽

Jakub Prażmo ◽

Wojciech Kucharczyk

Keyword(s):

Physical Properties ◽

Injection Moulding ◽

Glass Fibers ◽

Climatic Conditions ◽

Natural Ageing ◽

Elastic Deformations ◽

Polypropylene Composites ◽

Pp Composites ◽

Short Glass ◽

Transverse Shrinkage

The present work investigates the effect of natural weathering on polypropylene (PP) composites containing short glass fibers and talc. The samples of PP composites obtained by injection moulding were submitted to nine months of natural ageing (from March to November 2012). It observed effects of climatic conditions on some physical properties such as hardness, longitudinal and transverse shrinkage as well as plastic and elastic deformations.

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Development and verification of mechanical characteristics of a composite material made of a thermoplastic matrix and short glass fibers

Eastern-European Journal of Enterprise Technologies ◽

10.15587/1729-4061.2021.243149 ◽

2021 ◽

Vol 5 (12(113)) ◽

pp. 30-38

Author(s):

Madina Isametova ◽

Gazel Abilezova ◽

Nikolay Dishovsky ◽

Petar Velev

Keyword(s):

Mechanical Properties ◽

Finite Element ◽

Composite Material ◽

Computer Modeling ◽

Glass Fibers ◽

Field Tests ◽

Mechanical Tests ◽

Macro Level ◽

Stage Of Development ◽

Short Glass

The paper presents the results of computer modeling and prediction of the mechanical properties of composite materials with a polycarbonate matrix filled with short glass inclusions. At the micro-level, the influence of the volume of inclusions on the mechanical properties of the designed composite based on polycarbonate matrix is studied in the DIGIMAT (France) program. It was found that with a ratio of the sizes of inclusions in the range of 468÷60, the particles have a needle shape, and the material with such inclusions has a higher stress limit and elastic modulus than with a shape coefficient less than 50. The components of the fiber orientation tensor were also determined, at which the values of computer modeling are in good agreement with experimental data. The influence of the size of the finite element grid on the characteristics of the composite at the macro level was studied, and recommendations were given for choosing the size of the face of the finite element. The adequacy of computer models was confirmed by the results of field tests. The paper presents the results of testing flat samples made by injection molding technology. Mechanical tests were carried out for three variants of samples made of composite material based on a polycarbonate matrix with 10 %, 20 % and 30 % inclusions. The discrepancy between the experimental and computer results for samples with 10 %, 20 % content of short chopped fibers is explained by the influence of technological factors on the properties of the material at the macro-level. The conducted research allowed us to develop a computer modeling technique used at the stage of development of polymer composites based on thermoplastic matrices with short glass inclusions

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Development of a Prediction Model for the Mechanical Properties of Polypropylene Composites Reinforced by Talc and Short Glass Fibers

Composites Research ◽

10.7234/composres.2013.26.4.245 ◽

2013 ◽

Vol 26 (4) ◽

pp. 245-253

Author(s):

Soon Kim ◽

Dongil Son ◽

Donghyuk Choi ◽

Inchan Jeong ◽

Young-Bin Park ◽

...

Keyword(s):

Mechanical Properties ◽

Prediction Model ◽

Glass Fibers ◽

Polypropylene Composites ◽

Short Glass

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Characteristics of elastic waves generated by crack initiation in aluminum alloys under fatigue loading

Journal of Materials Research ◽

10.1557/jmr.2001.0241 ◽

2001 ◽

Vol 16 (6) ◽

pp. 1745-1751 ◽

Cited By ~ 8

Author(s):

Kiwoo Nam ◽

Ajit Mal

Keyword(s):

Aluminum Alloys ◽

Crack Initiation ◽

Elastic Waves ◽

Spectral Characteristics ◽

Power Spectra ◽

Fatigue Loading ◽

Fatigue Tests ◽

Static Tests ◽

The Waves ◽

Type Of Fracture

The characteristics of elastic waves emanating from crack initiation in 2024 and 5052 aluminum alloys subject to static and fatigue loading were investigated through laboratory experiments. The objective of the study was to determine the differences in the properties of the signals generated from static and fatigue tests and also to examine if the sources of the waves could be identified from the temporal and spectral characteristics of the acoustic emission waveforms. The signals were recorded using nonresonant, flat, broadband transducers attached to the surface of the alloy specimens. The time dependence and power spectra of the signals recorded during the tests were examined and classified according to their special features. Three distinct types of signals were observed. The waveforms and their power spectra were found to be dependent on the material and the type of fracture associated with the signals. Analysis of the waveforms indicated that some signals could be attributed to plastic deformation associated with static tests. The potential application of the approach in health monitoring of aging aircraft structures using a network of surface mounted broadband sensors is discussed.

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Correlation of fatigue behavior and dynamic mechanical properties of hybrid composites of polypropylene/short glass fibers/hollow glass beads

Journal of Thermoplastic Composite Materials ◽

10.1177/0892705721993190 ◽

2021 ◽

pp. 089270572199319

Author(s):

Gustavo B Carvalho

Keyword(s):

Stress Relaxation ◽

Flexural Strength ◽

Relaxation Rate ◽

Hybrid Composites ◽

Fatigue Behavior ◽

Glass Fibers ◽

Glass Beads ◽

Hollow Glass ◽

Dynamic Mechanical ◽

Short Glass

Ternary hybrid composites of Polypropylene (PP)/Short Glass Fibers (GF)/Hollow Glass Beads (HGB) were prepared using untreated and aminosilane-treated HGB, compatibilized with maleated-PP, and with varying total and relative GF/HGB contents. Static/short-term flexural strength properties data revealed, through lower flexural strength values, that the presence of untreated HGB particles induces to fiber-polymer interfacial decoupling at much higher extent than in the presence of aminosilane-treated HGB particles. This phenomenon is also evident when evaluating the data from displacement-controlled three-point bending fatigue tests. Monitored up to 106 cycles, the analyzed hybrid composites presented distinct performance relative to their fatigue stress relaxation rate: the lower the matrix-reinforcements’ interfacial adhesion, more pronounced the stress relaxation rate as a function of the number of fatigue cycles. Dynamic Mechanical Thermal Analysis (DMTA) results could successfully reveal the hybrid composites behavior at the microstructural level when they were submitted to both static flexural test and fatigue, depending on the degree of interfacial interactions between the polymer matrix of PP and the hybrid reinforcements of GF and HGB (with and without aminosilane surface treatment).

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A Fatigue Damage Model for Life Prediction of Injection-Molded Short Glass Fiber-Reinforced Thermoplastic Composites

Polymers ◽

10.3390/polym13142250 ◽

2021 ◽

Vol 13 (14) ◽

pp. 2250

Author(s):

Mohammad Amjadi ◽

Ali Fatemi

Keyword(s):

Injection Molding ◽

Glass Fiber ◽

Fatigue Damage ◽

Life Prediction ◽

Glass Fibers ◽

Damage Model ◽

Fiber Reinforced ◽

Short Glass Fiber ◽

Glass Fiber Reinforced ◽

Short Glass

Short glass fiber-reinforced (SGFR) thermoplastics are used in many industries manufactured by injection molding which is the most common technique for polymeric parts production. Glass fibers are commonly used as the reinforced material with thermoplastics and injection molding. In this paper, a critical plane-based fatigue damage model is proposed for tension–tension or tension–compression fatigue life prediction of SGFR thermoplastics considering fiber orientation and mean stress effects. Temperature and frequency effects were also included by applying the proposed damage model into a general fatigue model. Model predictions are presented and discussed by comparing with the experimental data from the literature.

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