Effect of relative humidity on mechanical properties of a woven thermoplastic composite for automotive application

Malpot, Amélie; Touchard, Fabienne; Bergamo, Sébastien

doi:10.1016/j.polymertesting.2015.10.010

Cited by 31 publications

(17 citation statements)

References 27 publications

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“…Woven reinforced thermoplastic composite materials are gaining interest in automotive applications [1][2][3], due to their important weight reduction in comparison with applications using metals. In addition, compared to a unidirectional rein-forcement, a woven fabric allows a better equilibrium and uniformity of the mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Damage Evaluation in Woven Glass Reinforced Polyamide 6.6/6 Composites Using Ultrasound Phase-Shift Analysis and X-ray Tomography

et al. 2018

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The paper proposes a new experimental methodology, based on ultrasonic measurements, that aims at evaluating the anisotropic damage in woven semi-crystalline polymer composites through new damage indicators. Due to their microstructure, woven composite materials are characterized by an anisotropic evolution of damage induced by different damage mechanisms occurring at the micro or mesoscopic scales. In this work, these damage modes in polyamide 6.6/6-woven glass fiber reinforced composites have been investigated qualitatively and quantitatively by X-ray micro-computed tomography (mCT) analysis on composite samples cut according to two orientations with respect to the mold flow direction. Composite samples are initially damaged at different levels during preliminary interrupted tensile tests. Ultrasonic investigations using C-scan imaging have been carried out without yielding significant results. Consequently, an ultrasonic method for stiffness constants estimation based on the bulk and guided wave velocity measurements is applied. Two damage indicators are then proposed. The first consists in calculating the Frobenius norm of the obtained stiffness matrix. The second is computed using the phase shift between two ultrasonic signals respectively measured on the tested samples and an undamaged reference sample. Both X-ray mCT and ultrasonic investigations show a higher damage evolution with respect to the applied stress for the samples oriented at 45 • from the warp direction compared to the samples in the 0 • configuration. The evolution of the second ultrasonic damage indicator exhibits a good correlation with the void volume fraction evolution estimated by mCT as well as with the damage calculated using the measured elastic modulus reduction. The merit of this research is of importance for the automotive industry.

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Section: Introductionmentioning

confidence: 99%

Damage Evaluation in Woven Glass Reinforced Polyamide 6.6/6 Composites Using Ultrasound Phase-Shift Analysis and X-ray Tomography

et al. 2018

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“…Several studies have shown that the water content of polymers and polymer matrix composites, including Elium Õ resins, can significantly influence their mechanical behaviour and damage scenario. [48][49][50][51][52] The long-term water content varies as a function of the %RH of the material exposure environment. As tensile tests could last up to 12 h, the use of a moisture content sensor ensured that temperature effect could be analysed without undergoing a coupling with a potential moisture effect.…”

Section: Quasi-static Tensile Tests On Composite Specimensmentioning

confidence: 99%

Effect of temperature on damage mechanisms and mechanical behaviour of an acrylic-thermoplastic-matrix and glass-fibre-reinforced composite

Boissin

Bois

Wahl

et al. 2020

Journal of Composite Materials

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The mechanical response of polymer matrix composites exhibits a temperature dependency even if the service temperature range is lower than the glass transition temperature of the polymer matrix. This dependency is mainly due to the temperature effect on the mechanical behaviour of the polymer matrix. However, the micro- and meso-structures driving the composite anisotropy and local stress distribution play an essential role regarding the effect of temperature on damage mechanisms specific to reinforced polymers. There are few data in the literature on the sensitivity to temperature of damage mechanisms and scenarios of polymer matrix composites regardless of loading type. In this paper, after a synthetic literature review of the effect of temperature on polymers and polymer composites, several complementary tests are proposed to analyse the temperature effect on damage mechanisms undergone by laminated composites under in-plane quasi static loadings. These tests are applied to an acrylic-thermoplastic composite reinforced by glass fibres in its service temperature range of –20℃ to 60℃. The results show that the testing temperature has a significant impact on the mechanical response and damage mechanisms of the composite material in the selected temperature range, which is markedly lower than the glass transition temperature (around 100℃). While the temperature rise generates a gradual decrease in matrix stiffness and strength, the increase in matrix ductility associated to the stress heterogeneity in the composite microstructure produces a rise in the transverse cracking threshold and removes this damage mode during quasi-static tensile tests when the temperature shifts from 15℃ to 40℃.

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“…The thermoplastic matrix is a semi-crystalline polymer, the polyamide 6.6, also called PA66. This resin has the particularity to be very sensitive to moisture absorption : the polyamid can absorb 2% to 5% moisture, depending on the relative humidity of the specimen [10], [11]. This important sensitivity to moisture has a direct impact on the mechanical properties (like the Young modulus or the ultimate tensile strength) [8], [12].…”

Section: Materials and Conditioningmentioning

confidence: 99%

Experimental monitoring of the self-heating properties of thermoplastic composite materials during tensile and cyclic tests

et al. 2018

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Abstract. The sizing of industrial structures with a given material requires to understand completely its fatigue behaviour. Yet, the full estimation of the fatigue lifetime of a material requires time-consuming and expensive fatigue testing campaigns, and a huge number of samples. An alternative experimental procedure is based on the monitoring of the self-heating properties of the studied material. The aim is to correlate the fatigue limit with a change of the thermal behaviour of the material during the self-heating tests. The main advantage of these tests is that they need only a limited number of mechanical cycles, and require few samples to test. Ultimately, self-heating tests lead to an accelerated estimation of the fatigue behaviour. The purpose of the present paper is to validate this approach for a woven carbon/thermoplastic composite material.

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Effect of relative humidity on mechanical properties of a woven thermoplastic composite for automotive application

Cited by 31 publications

References 27 publications

Damage Evaluation in Woven Glass Reinforced Polyamide 6.6/6 Composites Using Ultrasound Phase-Shift Analysis and X-ray Tomography

Damage Evaluation in Woven Glass Reinforced Polyamide 6.6/6 Composites Using Ultrasound Phase-Shift Analysis and X-ray Tomography

Effect of temperature on damage mechanisms and mechanical behaviour of an acrylic-thermoplastic-matrix and glass-fibre-reinforced composite

Experimental monitoring of the self-heating properties of thermoplastic composite materials during tensile and cyclic tests

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