https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Tue, 21 Apr 2026 13:58:09 GMT 2026-04-21T13:58:09Z http://hdl.handle.net/10985/9872 Comparison of damage behaviour of different plant fibre composites under laser impact loading TOUCHARD, Fabienne; BERTHE, Laurent; MALINOWSKI, Paweł H; OPOKA, Szymon; BOUSTIE, Michel; CHOCINSKI-ARNAULT, Laurence; OSTACHOWICZ, Wiesław M. The high strain rate behaviour of the eco-composites, when submitted to laser impact loading, is not well known yet. Crucial questions are still open: influence of plant fiber length and distribution on the composite impact behaviour, types of damage induced by impact loading, the way the failure occurs, etc. We present the very first results of a collaborative research involving the institutions PPRIME- Poitiers and PIMM-Paris, and IMP PAN-Gdansk-Poland. A comparison of laser shock induced damage is realised, based on observations of sample back faces for several types of eco-composites. Spallation, residual blister and inside delamination, depending on the fibre length in tested composites have been observed. The ability of the Terahertz technique for internal damage detection is demonstrated. Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/10985/9872 2015-01-01T00:00:00Z TOUCHARD, Fabienne BERTHE, Laurent MALINOWSKI, Paweł H OPOKA, Szymon BOUSTIE, Michel CHOCINSKI-ARNAULT, Laurence OSTACHOWICZ, Wiesław M. The high strain rate behaviour of the eco-composites, when submitted to laser impact loading, is not well known yet. Crucial questions are still open: influence of plant fiber length and distribution on the composite impact behaviour, types of damage induced by impact loading, the way the failure occurs, etc. We present the very first results of a collaborative research involving the institutions PPRIME- Poitiers and PIMM-Paris, and IMP PAN-Gdansk-Poland. A comparison of laser shock induced damage is realised, based on observations of sample back faces for several types of eco-composites. Spallation, residual blister and inside delamination, depending on the fibre length in tested composites have been observed. The ability of the Terahertz technique for internal damage detection is demonstrated. http://hdl.handle.net/10985/16782 Numerical modeling of laser-induced shock experiments for the development of the adhesion test for bonded composite materials ECAULT, Romain; TOUCHARD, Fabienne; BOUSTIE, Michel; BERTHE, Laurent; DOMINGUEZ, Nicolas In this work, laser shock experiments on composite material are modeled. Focus is made on the development of a reliable numerical model to be used for the laser shock wave adhesion test of bonded composites. Technique principle is explained as well as the laser shock experiment procedure. Then, the numerical investigations are presented. A calibration method is given to set the model input parameters, and the modeling choices are detailed. Dynamic material parameters are identified thanks to experimental results, and validated through a complete campaign of laser shocks on various carbon fiber reinforced plastic (CFRP) materials (monolithic and bonded). Finally, numerical results for bonded composites are discussed. They enable to understand the stress distribution within the composite assembly during the wave propagation. This is a key step toward the development of a reliable and controlled laser shock adhesion test. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10985/16782 2016-01-01T00:00:00Z ECAULT, Romain TOUCHARD, Fabienne BOUSTIE, Michel BERTHE, Laurent DOMINGUEZ, Nicolas In this work, laser shock experiments on composite material are modeled. Focus is made on the development of a reliable numerical model to be used for the laser shock wave adhesion test of bonded composites. Technique principle is explained as well as the laser shock experiment procedure. Then, the numerical investigations are presented. A calibration method is given to set the model input parameters, and the modeling choices are detailed. Dynamic material parameters are identified thanks to experimental results, and validated through a complete campaign of laser shocks on various carbon fiber reinforced plastic (CFRP) materials (monolithic and bonded). Finally, numerical results for bonded composites are discussed. They enable to understand the stress distribution within the composite assembly during the wave propagation. This is a key step toward the development of a reliable and controlled laser shock adhesion test. http://hdl.handle.net/10985/13810 Study of plant fibre composites with damage induced by laser and mechanical impacts MALINOWSKI, Paweł H.; SORRENTINO, Luigi; VASCONCELLOS, Davi Silva De; BERTHE, Laurent; GONZALEZ, Pedro Pascual; CHOCINSKI-ARNAULT, Laurence; BOUSTIE, Michel; TOUCHARD, Fabienne; OSTACHOWICZ, Wiesław M. Polymer composite materials provide good strength to weight ratio and tailored mechanical properties thanks to the reinforcing fibres. Until recently, the need for taking into account the whole life cycle of a composite structure was neglected and only the service aspects were important. Today, the designers of a new composite structure have to take into account the environmental aspects from the sustainability of raw materials to the management of end life products. There are recycling issues related to the most popular composites. A solution for the recycling issue can be sought in green composites with reinforcing fibre originating from plants. The behaviour of eco-composites, when subjected to laser or mechanical impact loadings, is not well known yet. Short fibre composites were made with spruce fibres. Another set of samples was made of flax fibres. Also a woven hemp fabric-based eco-composite was investigated. A fully synthetic woven composite was used for comparison with green composites. Mechanical impacts were performed by means of a falling dart impact testing machine. Laser impacts were made with high power laser source. Four assessment techniques were employed in order to analyse and compare impact damage. Damage detection thresholds for each material and technique were obtained. Mon, 01 Jan 2018 00:00:00 GMT http://hdl.handle.net/10985/13810 2018-01-01T00:00:00Z MALINOWSKI, Paweł H. SORRENTINO, Luigi VASCONCELLOS, Davi Silva De BERTHE, Laurent GONZALEZ, Pedro Pascual CHOCINSKI-ARNAULT, Laurence BOUSTIE, Michel TOUCHARD, Fabienne OSTACHOWICZ, Wiesław M. Polymer composite materials provide good strength to weight ratio and tailored mechanical properties thanks to the reinforcing fibres. Until recently, the need for taking into account the whole life cycle of a composite structure was neglected and only the service aspects were important. Today, the designers of a new composite structure have to take into account the environmental aspects from the sustainability of raw materials to the management of end life products. There are recycling issues related to the most popular composites. A solution for the recycling issue can be sought in green composites with reinforcing fibre originating from plants. The behaviour of eco-composites, when subjected to laser or mechanical impact loadings, is not well known yet. Short fibre composites were made with spruce fibres. Another set of samples was made of flax fibres. Also a woven hemp fabric-based eco-composite was investigated. A fully synthetic woven composite was used for comparison with green composites. Mechanical impacts were performed by means of a falling dart impact testing machine. Laser impacts were made with high power laser source. Four assessment techniques were employed in order to analyse and compare impact damage. Damage detection thresholds for each material and technique were obtained. http://hdl.handle.net/10985/18783 Laser shock adhesion test numerical optimization for composite bonding assessment ECAULT, Romain; TOUCHARD, Fabienne; BERTHE, Laurent; BOUSTIE, Michel The present work presents the latest development of laser shock adhesion test (LASAT) technology, targeting the weak bond detection in bonded aeronautic structures. This problematic is still holding back a wider use of bonding, which could however be a significant breakthrough in the way of assembling parts. By mechanically loading the bondline thanks to laser-induced shock waves, LASAT acts as proof test to reveal the presence of local weaknesses. In the present paper, focus is made on the optimization of the laser shock parameters regarding the assembly to test. Objective is to avoid loading too much the composite, thus avoiding damage, to increase the test performances. Numerical modelling is used, following a specific methodology, to understand the phenomena and identify the key parameters. The basic laser shock configuration was first investigated. Due to the stress distribution, this setting allows one to test a bond whose strength is equal or below 40% of composite inter-laminar strength. The effects of the laser focal spot on the stress distribution are also quantified. A 4 mm diameter shows good performances for the assembly to test. For the first time, three different optimizations are proposed: tunable pulse duration, double pulses on the front face and symmetrical laser shocks. They are first theoretically described. Numerical results then support these configurations’ performances. The double pulse solution makes it possible to test a bond strength equal or inferior to 80% of composite inter-laminar strength, when symmetrical pulses enable to reach 100% thanks to a sharp stress distribution. These results are validated by experimental evidence that is also presented. Finally, the present work offers helpful information for the development and deployment of LASAT for aeronautic bonded structures. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/18783 2020-01-01T00:00:00Z ECAULT, Romain TOUCHARD, Fabienne BERTHE, Laurent BOUSTIE, Michel The present work presents the latest development of laser shock adhesion test (LASAT) technology, targeting the weak bond detection in bonded aeronautic structures. This problematic is still holding back a wider use of bonding, which could however be a significant breakthrough in the way of assembling parts. By mechanically loading the bondline thanks to laser-induced shock waves, LASAT acts as proof test to reveal the presence of local weaknesses. In the present paper, focus is made on the optimization of the laser shock parameters regarding the assembly to test. Objective is to avoid loading too much the composite, thus avoiding damage, to increase the test performances. Numerical modelling is used, following a specific methodology, to understand the phenomena and identify the key parameters. The basic laser shock configuration was first investigated. Due to the stress distribution, this setting allows one to test a bond whose strength is equal or below 40% of composite inter-laminar strength. The effects of the laser focal spot on the stress distribution are also quantified. A 4 mm diameter shows good performances for the assembly to test. For the first time, three different optimizations are proposed: tunable pulse duration, double pulses on the front face and symmetrical laser shocks. They are first theoretically described. Numerical results then support these configurations’ performances. The double pulse solution makes it possible to test a bond strength equal or inferior to 80% of composite inter-laminar strength, when symmetrical pulses enable to reach 100% thanks to a sharp stress distribution. These results are validated by experimental evidence that is also presented. Finally, the present work offers helpful information for the development and deployment of LASAT for aeronautic bonded structures. http://hdl.handle.net/10985/8417 Development of a laser shock adhesion test for the assessment of weak adhesive bonded CFRP structures EHRHART, Bastien; ECAULT, Romain; TOUCHARD, Fabienne; BOUSTIE, Michel; BERTHE, Laurent; BOCKENHEIMER, Clemens; VALESKE, Bernd Adhesive bondin,g bas a great poœnlial far future ligbtweight bigb-loaded structures in the a.eronautic industiy. A preœquisite for sucb an application is dtat the bond quality of the adhesive joint can be assessed in a non-destructive way. However, the use of da.ssicaJ Non•DesiiUctive Techniques (NDT) does not aUow the evaluation of the adhesion stren,gt:h of an adhesive bond yet This paper pn!sents an investigation made on weak composite bonds in on!er to develop a laser shock wave adhesion test First, the procedure to produce controlled weak bonds is desaibed. CFRP bonded samples are pn!pared in a spedfic way and characterized by ultrasonic techniques to assess the absence of any detectable defect. 1ben, for sorne of the .samples, their bond streDgth is evaluated by mechanical destructive œsts and ether .samples are loaded by v.arious intensity lasers shocks. The obtained results help to understand the behavior of the composite bonds under Jaser shock loading:. thanks to two post-mortem techrùques. 1becorrelation between the laser parameterS and the induced damage is demon.strated, The potential of the laser shock. technique to dl.saiminate different bond quallties is shawn, and the need for the œst optinùzationlsdÛ(U Wed, 01 Jan 2014 00:00:00 GMT http://hdl.handle.net/10985/8417 2014-01-01T00:00:00Z EHRHART, Bastien ECAULT, Romain TOUCHARD, Fabienne BOUSTIE, Michel BERTHE, Laurent BOCKENHEIMER, Clemens VALESKE, Bernd Adhesive bondin,g bas a great poœnlial far future ligbtweight bigb-loaded structures in the a.eronautic industiy. A preœquisite for sucb an application is dtat the bond quality of the adhesive joint can be assessed in a non-destructive way. However, the use of da.ssicaJ Non•DesiiUctive Techniques (NDT) does not aUow the evaluation of the adhesion stren,gt:h of an adhesive bond yet This paper pn!sents an investigation made on weak composite bonds in on!er to develop a laser shock wave adhesion test First, the procedure to produce controlled weak bonds is desaibed. CFRP bonded samples are pn!pared in a spedfic way and characterized by ultrasonic techniques to assess the absence of any detectable defect. 1ben, for sorne of the .samples, their bond streDgth is evaluated by mechanical destructive œsts and ether .samples are loaded by v.arious intensity lasers shocks. The obtained results help to understand the behavior of the composite bonds under Jaser shock loading:. thanks to two post-mortem techrùques. 1becorrelation between the laser parameterS and the induced damage is demon.strated, The potential of the laser shock. technique to dl.saiminate different bond quallties is shawn, and the need for the œst optinùzationlsdÛ(U http://hdl.handle.net/10985/9902 Experimental and numerical investigations of shock and shear wave propagation induced by femtosecond laser irradiation in epoxy resins ECAULT, Romain; BERTHE, Laurent; TOUCHARD, Fabienne; BOUSTIE, Michel; LESCOUTE, Emilien; SOLLIER, Arnaud; VOILLAUME, Hubert In this work, original shock experiments are presented. Laser-induced shock and shear wave propagations have been observed in an epoxy resin, in the case of femtosecond laser irradiation. A specific time-resolved shadowgraphy setup has been developed using the photoelasticimetry principle to enhance the shear wave observation. Shear waves have been observed in epoxy resin after laser irradiation. Their propagation has been quantified in comparison with the main shock propagation. A discussion, hinging on numerical results, is finally given to improve understanding of the phenomenon. Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/10985/9902 2015-01-01T00:00:00Z ECAULT, Romain BERTHE, Laurent TOUCHARD, Fabienne BOUSTIE, Michel LESCOUTE, Emilien SOLLIER, Arnaud VOILLAUME, Hubert In this work, original shock experiments are presented. Laser-induced shock and shear wave propagations have been observed in an epoxy resin, in the case of femtosecond laser irradiation. A specific time-resolved shadowgraphy setup has been developed using the photoelasticimetry principle to enhance the shear wave observation. Shear waves have been observed in epoxy resin after laser irradiation. Their propagation has been quantified in comparison with the main shock propagation. A discussion, hinging on numerical results, is finally given to improve understanding of the phenomenon. http://hdl.handle.net/10985/8109 A study of composite material damage induced by laser shock waves ESCAULT, Romain; BOUSTIE, Michel; TOUCHARD, Fabienne; PONS, Frédéric; BERTHE, Laurent; CHOCINSKI-ARNAULT, Laurence; EHRHART, Bastien; BOCKENHEIMER, Clemens A laser shock wave technique has been used to study the damage tolerance of T800/M21 CFRP (Carbon Fiber Reinforced Polymer) composite material with different lay_ups. Different levels of damage have been created according to various laser irradiation conditions. Several characterization methods such as Optical Microscopy, X-ray Radiography, or Interferometric Confocal Microscopy have been used to quantify these defects. The nature of the defects induced by the shock wave propagation has been studied. The sensitivity of the composite material damage to the shock conditions has been shown and quantified. Moreover, the experimental results gathered with each technique have been compared to each other and it leads to a better understanding of the CFRP behavior under high dynamic loading. These original results have enabled the definition of a specific damage criterion for CFRP under dynamic loading. Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/10985/8109 2013-01-01T00:00:00Z ESCAULT, Romain BOUSTIE, Michel TOUCHARD, Fabienne PONS, Frédéric BERTHE, Laurent CHOCINSKI-ARNAULT, Laurence EHRHART, Bastien BOCKENHEIMER, Clemens A laser shock wave technique has been used to study the damage tolerance of T800/M21 CFRP (Carbon Fiber Reinforced Polymer) composite material with different lay_ups. Different levels of damage have been created according to various laser irradiation conditions. Several characterization methods such as Optical Microscopy, X-ray Radiography, or Interferometric Confocal Microscopy have been used to quantify these defects. The nature of the defects induced by the shock wave propagation has been studied. The sensitivity of the composite material damage to the shock conditions has been shown and quantified. Moreover, the experimental results gathered with each technique have been compared to each other and it leads to a better understanding of the CFRP behavior under high dynamic loading. These original results have enabled the definition of a specific damage criterion for CFRP under dynamic loading. http://hdl.handle.net/10985/8061 Observation of the shock wave propagation induced by a high-power laser irradiation into an epoxy material ESCAULT, Romain; BERTHE, Laurent; BOUSTIE, Michel; TOUCHARD, Fabienne; LESCOUTE, Emilien; SOLLIER, Arnaud; MERCIER, Patrick; BERNIER, Jacky The propagation of laser-induced shock waves in a transparent epoxy sample is investigated by optical shadowgraphy. The shock waves are generated by a focused laser (3 ns pulse duration—1.2 to 3.4TWcm−2) producing pressure from 44 to 98.9 GPa. It is observed that the shock wave and the release wave created by the shock reverberation at the rear face are both followed by a dark zone in the pictures. This corresponds to the creation of a tensile zone resulting from the crossing on the loading axis of the release waves coming from the edge of the impact area (2D effects). After the laser shock experiment, the residual stresses in the targets are identified and quantified through a photoelasticimetry analysis of the recovered samples. This work results in a new set of original data which can be directly used to validate numerical models implemented to reproduce the behaviour of epoxy under extreme strain rate loading. The residual stresses observed prove that the high-pressure shocks can modify the pure epoxy properties, which could have an influence on the use made of these materials. Wed, 01 Jan 2014 00:00:00 GMT http://hdl.handle.net/10985/8061 2014-01-01T00:00:00Z ESCAULT, Romain BERTHE, Laurent BOUSTIE, Michel TOUCHARD, Fabienne LESCOUTE, Emilien SOLLIER, Arnaud MERCIER, Patrick BERNIER, Jacky The propagation of laser-induced shock waves in a transparent epoxy sample is investigated by optical shadowgraphy. The shock waves are generated by a focused laser (3 ns pulse duration—1.2 to 3.4TWcm−2) producing pressure from 44 to 98.9 GPa. It is observed that the shock wave and the release wave created by the shock reverberation at the rear face are both followed by a dark zone in the pictures. This corresponds to the creation of a tensile zone resulting from the crossing on the loading axis of the release waves coming from the edge of the impact area (2D effects). After the laser shock experiment, the residual stresses in the targets are identified and quantified through a photoelasticimetry analysis of the recovered samples. This work results in a new set of original data which can be directly used to validate numerical models implemented to reproduce the behaviour of epoxy under extreme strain rate loading. The residual stresses observed prove that the high-pressure shocks can modify the pure epoxy properties, which could have an influence on the use made of these materials. http://hdl.handle.net/10985/13835 Study of plant fibre composites with damage induced by laser and mechanical impacts MALINOWSKI, Paweł H.; VASCONCELLOS, Davi Silva De; TOUCHARD, Fabienne; OSTACHOWICZ, Wiesław M.; BERTHE, Laurent; GONZALEZ, Pedro Pascual; CHOCINSKI-ARNAULT, Laurence Polymer composite materials provide good strength to weight ratio and tailored mechanical properties thanks to the reinforcing fibres. Until recently, the need for taking into account the whole life cycle of a composite structure was neglected and only the service aspects were important. Today, the designers of a new composite structure have to take into account the environmental aspects from the sustainability of raw materials to the management of end life products. There are recycling issues related to the most popular composites. A solution for the recycling issue can be sought in green composites with reinforcing fibre originating from plants. The behaviour of eco-composites, when subjected to laser or mechanical impact loadings, is not well known yet. Short fibre composites were made with spruce fibres. Another set of samples was made of flax fibres. Also a woven hemp fabric-based eco-composite was investigated. A fully synthetic woven composite was used for comparison with green composites. Mechanical impacts were performed by means of a falling dart impact testing machine. Laser impacts were made with high power laser source. Four assessment techniques were employed in order to analyse and compare impact damage. Damage detection thresholds for each material and technique were obtained. Mon, 01 Jan 2018 00:00:00 GMT http://hdl.handle.net/10985/13835 2018-01-01T00:00:00Z MALINOWSKI, Paweł H. VASCONCELLOS, Davi Silva De TOUCHARD, Fabienne OSTACHOWICZ, Wiesław M. BERTHE, Laurent GONZALEZ, Pedro Pascual CHOCINSKI-ARNAULT, Laurence Polymer composite materials provide good strength to weight ratio and tailored mechanical properties thanks to the reinforcing fibres. Until recently, the need for taking into account the whole life cycle of a composite structure was neglected and only the service aspects were important. Today, the designers of a new composite structure have to take into account the environmental aspects from the sustainability of raw materials to the management of end life products. There are recycling issues related to the most popular composites. A solution for the recycling issue can be sought in green composites with reinforcing fibre originating from plants. The behaviour of eco-composites, when subjected to laser or mechanical impact loadings, is not well known yet. Short fibre composites were made with spruce fibres. Another set of samples was made of flax fibres. Also a woven hemp fabric-based eco-composite was investigated. A fully synthetic woven composite was used for comparison with green composites. Mechanical impacts were performed by means of a falling dart impact testing machine. Laser impacts were made with high power laser source. Four assessment techniques were employed in order to analyse and compare impact damage. Damage detection thresholds for each material and technique were obtained.