P. Delobelle | University of Franche-Comte (original) (raw)
Papers by P. Delobelle
Structural Control and Health Monitoring, 2007
... Once this value is determined, the optimal modal feedback gains of the controller is computed... more ... Once this value is determined, the optimal modal feedback gains of the controller is computed and only the modes having a high energy are controlled. Devasia et al. ... 2007; 14:660680 DOI: 10.1002/stc Page 8. So, by choosing *wğxpŞ ¼ 0 h 2 Á e31 Á l Á V Á @ *wğxp; tŞ @x ...
Optics Communications, 2011
ABSTRACT A detailed study of the morphology of nano-craters drilled in borosilicate glass by sing... more ABSTRACT A detailed study of the morphology of nano-craters drilled in borosilicate glass by single shot femtosecond laser ablation near the ablation threshold has been performed by scanning electron microscopy, atomic force microscopy and scanning electron microscopy imaging after focused ion beam sectioning. The influence of the numerical aperture (NA=0.4 and 0.8), the pulse energy (16nJ
Materials Science and Engineering: A, 1999
In order to characterize the mechanical behavior of thin polyimide films deposited on a GaAs subs... more In order to characterize the mechanical behavior of thin polyimide films deposited on a GaAs substrate in a membrane configuration, bulging and nanoindentation tests are performed. By these means, Young’s modulus of polyimide films, with thicknesses on the micron scale is found to be equal to 2.8 GPa. These two different techniques, which do not rely on the same assumptions, give results in very good agreement. The tensile residual stress in the membranes due to the fabrication process is a decreasing function of the thickness: 12<σ0<25 MPa. These membranes are already employed as mechanical support for coplanar wave guides up to the millimeter wave range.
Materials Science and Engineering: A, 2001
ABSTRACT
Journal de Physique IV (Proceedings), 2003
ABSTRACT This paper proposes a damaged viscoplastic model to simulate, for different isotherms (3... more ABSTRACT This paper proposes a damaged viscoplastic model to simulate, for different isotherms (320, 350, 380, 400 and 420°C), the out-of-flux anisotropic mechanical behavior of Zircaloy-4 claddings in a stress relieved state over the fluence range 0-85.10$^{24}$ nm$^{-2}$ ($\rm E>l$MeV). The model, identified from uni and biaxial tests conducted at 350 and 4000°C, is validated from tests made at 320, 380 and 420°C. This model is able to simulate strain hardening under an internal pressure followed by a stress relaxation period, since the loading produces an interaction between the pellet and the cladding (thermal creep). Both the integration of a scalar state variable, characterizing the damage caused by a bombardment with neutrons, and the modification of the static recovery law allowed us to simulate the fast neutron flux effect (irradiation creep).
Metallurgical Transactions A, 1982
ABSTRACT
Metallurgical Transactions A, 1985
With the help of isothermic relaxation tests and internal friction, we have studied the mechanism... more With the help of isothermic relaxation tests and internal friction, we have studied the mechanism of a Snoek type reordering of heavy interstitials (oxygen, carbon, nitrogen) in tantalum, niobium, and iron. The kinetics and the amplitude of the stress relaxation conform to the general theory of the anelastic dipole due to Berry and Nowick. In an identical temperature range and on the same solid solutions, we have studied the effect of static strain aging on the yield point effect represented by the parameter Acr/cr. We show that, in accordance with the Schoeck and Seeger model, the first period of aging is due to the reorientation at short distance of the interstitials in the dislocation stress field. In fact, identification of the two phenomena leads to the relation Acr(t)/cr = aA~(t), with a close to the unity, which is in accordance with experiments.
Journal of Engineering Materials and Technology, 2000
ABSTRACT
International Journal of Plasticity, 1995
The comprehension and the quantitative description of the uni-and bidirectional ratchet phenomena... more The comprehension and the quantitative description of the uni-and bidirectional ratchet phenomena remains one of the final aspects to be correctly modelized by the phenomenological approaches employing a model with internal scalar and tensorial variables. Toward this end, the first step consists in creating a set of experimental basis of unidirectional and bidirectional ratchet. This has been done for an anstenitic stainless steel at 600°C. With the aid of alternating tension and torsion tests, the unidirectional ratchet can be quantified as a function of the maximal and average stresses. It is shown that the progressive strain only exists when the maximum stress is greater than 210 MPa and has a maximum for an average stress around 25 MPa and f'Lxed maximum stress of 300 MPa. The tension-torsion ratchet is examined in a detailed fashion, and the influence of both primary (axial direction) and secondary (shear direction) loading parameters on the progressive strain rate is demonstrated. To be able to integrate, during the modelization, the nonradiality effects present in this type of loading, several cyclic out-ofphase tension-torsion tests are performed (~ = 90°). At ambient temperature, several axialintemal pressure ratchet tests agree with the results obtained from tension-torsion tests. However, if ratchet tests were to be performed with two cyclic components (in or out of phase cyclic tension-torsion plus a static stress due to internal pressure), it can be shown that the rate of diametral ratchet is an increasing function of the phase angle between the cyclic components. This set of tests constitutes the experimental basis necessary for the modelization of the ratchet phenomena. It is then shown that it is possible to reasonably describe this set of experimental results after taking into account a few modifications in the definition of the evolutionary laws for the tensorial variables of kinematic hardening. The nature of the modifications introduced in the kinematic hardening variables depends on the type of ratchet to be modelized. For uniaxial loadings, the progressive strain is governed by average stress effects, whereas for multiaxial loadings it is essentially governed by directional flow effects.
Integrated Ferroelectrics, 2005
The development of micro-machined ultrasonic transducers on silicon opens new application fields ... more The development of micro-machined ultrasonic transducers on silicon opens new application fields for Si-based acoustic sensors operating in air or in liquids. In this work, we describe the fabrication of piezoelectric micro-machined ultrasonic transducers (pMUT) first dedicated to ultrasonic imaging applications that may be used as a mechanical to electrical energy transformer for energy scavenging purpose . We report on the fabrication of PZT/Si piezoelectric micro-machined ultrasonic transducers (pMUTs) first designed for acoustic applications and on tests of these devices as scavenging energy experiment.
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2000
Representing a new approach to ultrasound generation and detection, study on piezoelectric microm... more Representing a new approach to ultrasound generation and detection, study on piezoelectric micromachined ultrasonic transducers (pMUTs) has been a growing research area in recent years. Intensive research work has been directed on the deposition of lead zirconate titanate (PZT) films on silicon substrates for their excellent piezoelectric coefficients and electromechanical coupling coefficients. However, the high processing temperature required for PZT crystallization results in a low device yield and also makes it difficult to integrate with control circuits. In this paper, a fabrication technology of pMUTs based on piezoelectric P(VDF-TrFE) 70/30 copolymer films has been adopted, with the maximum processing temperature not exceeding 140°C allowing for post-IC compatibility. The entire processing procedures are simple and low cost, as compared with those of capacitive micromachined ultrasonic transducers (cMUTs) and ceramic-based pMUTs. The applications of the fabricated pMUTs as airborne ultrasonic transducers and transducer arrays have been demonstrated. Reasonably good device performances and high device yield have been achieved.
Journal of Microelectromechanical Systems, 1996
A vibration method for the evaluation of the stress in a membrane is presented. The principle is ... more A vibration method for the evaluation of the stress in a membrane is presented. The principle is based on the shift of the eigenfrequency of the modes due to the stress. The identification of the modes is obtained by an optical technique. The proposed method is applied to electrolytic nickel coatings. The results are compared with those obtained by X-ray
Le Journal de Physique IV, 1996
An unified viscoplastic model with internal kinematic variables is used to improve the descriptio... more An unified viscoplastic model with internal kinematic variables is used to improve the description of the uniaxial and proportional loadings performed in the pseudoelastic range of shape memory alloys. There is a good agreement between experimental data and simulations. Moreover, this constitutive set of equations is efficient for the description of internal loops and the isothermal cyclic loading which constitutes an important training process. In the future, some progress must be performed to take into account non proportional paths and anisothermal thermomechanical loadings.
Using an inverse method coupled with a numerical modelling (FEM) of the nanoindentation test done... more Using an inverse method coupled with a numerical modelling (FEM) of the nanoindentation test done on polypropylene modified by He + particles implantation and by electrons irradiation, we were able to quantify the modification of the viscoelastic properties due to these radiations. Those influences are superficial for the He + particles implantation and volumic for the e − irradiation. We suggest analytical formulation for both cases and present a method to analyse the gradient properties, which allowed us to found the theoretical value of the depth penetration of He + at 400 keV. This method seems promising at micrometric scale for the analysis of materials that present or not the gradient properties.
Structural Control and Health Monitoring, 2007
... Once this value is determined, the optimal modal feedback gains of the controller is computed... more ... Once this value is determined, the optimal modal feedback gains of the controller is computed and only the modes having a high energy are controlled. Devasia et al. ... 2007; 14:660680 DOI: 10.1002/stc Page 8. So, by choosing *wğxpŞ ¼ 0 h 2 Á e31 Á l Á V Á @ *wğxp; tŞ @x ...
Optics Communications, 2011
ABSTRACT A detailed study of the morphology of nano-craters drilled in borosilicate glass by sing... more ABSTRACT A detailed study of the morphology of nano-craters drilled in borosilicate glass by single shot femtosecond laser ablation near the ablation threshold has been performed by scanning electron microscopy, atomic force microscopy and scanning electron microscopy imaging after focused ion beam sectioning. The influence of the numerical aperture (NA=0.4 and 0.8), the pulse energy (16nJ
Materials Science and Engineering: A, 1999
In order to characterize the mechanical behavior of thin polyimide films deposited on a GaAs subs... more In order to characterize the mechanical behavior of thin polyimide films deposited on a GaAs substrate in a membrane configuration, bulging and nanoindentation tests are performed. By these means, Young’s modulus of polyimide films, with thicknesses on the micron scale is found to be equal to 2.8 GPa. These two different techniques, which do not rely on the same assumptions, give results in very good agreement. The tensile residual stress in the membranes due to the fabrication process is a decreasing function of the thickness: 12<σ0<25 MPa. These membranes are already employed as mechanical support for coplanar wave guides up to the millimeter wave range.
Materials Science and Engineering: A, 2001
ABSTRACT
Journal de Physique IV (Proceedings), 2003
ABSTRACT This paper proposes a damaged viscoplastic model to simulate, for different isotherms (3... more ABSTRACT This paper proposes a damaged viscoplastic model to simulate, for different isotherms (320, 350, 380, 400 and 420°C), the out-of-flux anisotropic mechanical behavior of Zircaloy-4 claddings in a stress relieved state over the fluence range 0-85.10$^{24}$ nm$^{-2}$ ($\rm E>l$MeV). The model, identified from uni and biaxial tests conducted at 350 and 4000°C, is validated from tests made at 320, 380 and 420°C. This model is able to simulate strain hardening under an internal pressure followed by a stress relaxation period, since the loading produces an interaction between the pellet and the cladding (thermal creep). Both the integration of a scalar state variable, characterizing the damage caused by a bombardment with neutrons, and the modification of the static recovery law allowed us to simulate the fast neutron flux effect (irradiation creep).
Metallurgical Transactions A, 1982
ABSTRACT
Metallurgical Transactions A, 1985
With the help of isothermic relaxation tests and internal friction, we have studied the mechanism... more With the help of isothermic relaxation tests and internal friction, we have studied the mechanism of a Snoek type reordering of heavy interstitials (oxygen, carbon, nitrogen) in tantalum, niobium, and iron. The kinetics and the amplitude of the stress relaxation conform to the general theory of the anelastic dipole due to Berry and Nowick. In an identical temperature range and on the same solid solutions, we have studied the effect of static strain aging on the yield point effect represented by the parameter Acr/cr. We show that, in accordance with the Schoeck and Seeger model, the first period of aging is due to the reorientation at short distance of the interstitials in the dislocation stress field. In fact, identification of the two phenomena leads to the relation Acr(t)/cr = aA~(t), with a close to the unity, which is in accordance with experiments.
Journal of Engineering Materials and Technology, 2000
ABSTRACT
International Journal of Plasticity, 1995
The comprehension and the quantitative description of the uni-and bidirectional ratchet phenomena... more The comprehension and the quantitative description of the uni-and bidirectional ratchet phenomena remains one of the final aspects to be correctly modelized by the phenomenological approaches employing a model with internal scalar and tensorial variables. Toward this end, the first step consists in creating a set of experimental basis of unidirectional and bidirectional ratchet. This has been done for an anstenitic stainless steel at 600°C. With the aid of alternating tension and torsion tests, the unidirectional ratchet can be quantified as a function of the maximal and average stresses. It is shown that the progressive strain only exists when the maximum stress is greater than 210 MPa and has a maximum for an average stress around 25 MPa and f'Lxed maximum stress of 300 MPa. The tension-torsion ratchet is examined in a detailed fashion, and the influence of both primary (axial direction) and secondary (shear direction) loading parameters on the progressive strain rate is demonstrated. To be able to integrate, during the modelization, the nonradiality effects present in this type of loading, several cyclic out-ofphase tension-torsion tests are performed (~ = 90°). At ambient temperature, several axialintemal pressure ratchet tests agree with the results obtained from tension-torsion tests. However, if ratchet tests were to be performed with two cyclic components (in or out of phase cyclic tension-torsion plus a static stress due to internal pressure), it can be shown that the rate of diametral ratchet is an increasing function of the phase angle between the cyclic components. This set of tests constitutes the experimental basis necessary for the modelization of the ratchet phenomena. It is then shown that it is possible to reasonably describe this set of experimental results after taking into account a few modifications in the definition of the evolutionary laws for the tensorial variables of kinematic hardening. The nature of the modifications introduced in the kinematic hardening variables depends on the type of ratchet to be modelized. For uniaxial loadings, the progressive strain is governed by average stress effects, whereas for multiaxial loadings it is essentially governed by directional flow effects.
Integrated Ferroelectrics, 2005
The development of micro-machined ultrasonic transducers on silicon opens new application fields ... more The development of micro-machined ultrasonic transducers on silicon opens new application fields for Si-based acoustic sensors operating in air or in liquids. In this work, we describe the fabrication of piezoelectric micro-machined ultrasonic transducers (pMUT) first dedicated to ultrasonic imaging applications that may be used as a mechanical to electrical energy transformer for energy scavenging purpose . We report on the fabrication of PZT/Si piezoelectric micro-machined ultrasonic transducers (pMUTs) first designed for acoustic applications and on tests of these devices as scavenging energy experiment.
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2000
Representing a new approach to ultrasound generation and detection, study on piezoelectric microm... more Representing a new approach to ultrasound generation and detection, study on piezoelectric micromachined ultrasonic transducers (pMUTs) has been a growing research area in recent years. Intensive research work has been directed on the deposition of lead zirconate titanate (PZT) films on silicon substrates for their excellent piezoelectric coefficients and electromechanical coupling coefficients. However, the high processing temperature required for PZT crystallization results in a low device yield and also makes it difficult to integrate with control circuits. In this paper, a fabrication technology of pMUTs based on piezoelectric P(VDF-TrFE) 70/30 copolymer films has been adopted, with the maximum processing temperature not exceeding 140°C allowing for post-IC compatibility. The entire processing procedures are simple and low cost, as compared with those of capacitive micromachined ultrasonic transducers (cMUTs) and ceramic-based pMUTs. The applications of the fabricated pMUTs as airborne ultrasonic transducers and transducer arrays have been demonstrated. Reasonably good device performances and high device yield have been achieved.
Journal of Microelectromechanical Systems, 1996
A vibration method for the evaluation of the stress in a membrane is presented. The principle is ... more A vibration method for the evaluation of the stress in a membrane is presented. The principle is based on the shift of the eigenfrequency of the modes due to the stress. The identification of the modes is obtained by an optical technique. The proposed method is applied to electrolytic nickel coatings. The results are compared with those obtained by X-ray
Le Journal de Physique IV, 1996
An unified viscoplastic model with internal kinematic variables is used to improve the descriptio... more An unified viscoplastic model with internal kinematic variables is used to improve the description of the uniaxial and proportional loadings performed in the pseudoelastic range of shape memory alloys. There is a good agreement between experimental data and simulations. Moreover, this constitutive set of equations is efficient for the description of internal loops and the isothermal cyclic loading which constitutes an important training process. In the future, some progress must be performed to take into account non proportional paths and anisothermal thermomechanical loadings.
Using an inverse method coupled with a numerical modelling (FEM) of the nanoindentation test done... more Using an inverse method coupled with a numerical modelling (FEM) of the nanoindentation test done on polypropylene modified by He + particles implantation and by electrons irradiation, we were able to quantify the modification of the viscoelastic properties due to these radiations. Those influences are superficial for the He + particles implantation and volumic for the e − irradiation. We suggest analytical formulation for both cases and present a method to analyse the gradient properties, which allowed us to found the theoretical value of the depth penetration of He + at 400 keV. This method seems promising at micrometric scale for the analysis of materials that present or not the gradient properties.