The Experts below are selected from a list of 3162 Experts worldwide ranked by ideXlab platform

Amelie Mainjot - One of the best experts on this subject based on the ideXlab platform.

  • influence of thermal expansion mismatch on Residual Stress Profile in veneering ceramic layered on zirconia measurement by hole drilling
    Dental Materials, 2015
    Co-Authors: Amelie Mainjot, Achref Najjar, Boris D Jakubowiczkohen, Michael Sadoun
    Abstract:

    Abstract Objectives Mismatch in thermal expansion coefficient between core and veneering ceramic (Δ α  =  α core  −  α veneer , ppm/°C) is reported as a crucial parameter influencing veneer fractures with Yttria-tetragonal-zirconia-polycrystal (Y-TZP) prostheses, which still constitutes a misunderstood problem. However, the common positive Δ α concept remains empirical. The objective of this study is to investigate the Δ α dependence of Residual Stress Profiles in veneering ceramic layered on Y-TZP frameworks. Methods The Stress Profile was measured with the hole-drilling method in bilayered disc samples of 20 mm diameter with a 0.7 mm thick Y-TZP framework and a 1.5 mm thick veneer layer. 3 commercial and 4 experimental veneering ceramics ( n  = 3 per group) were used to obtain different Δ α varying from −1.3 ppm/°C to +3.2 ppm/°C, which were determined by dilatometric analyses. Results Veneer fractures were observed in samples with Δ α  ≥ +2.3 or ≤−0.3 ppm/°C. Residual Stress Profiles measured in other groups showed compressive Stresses in the surface, these Stresses decreasing with depth and then becoming more compressive again near the interface. Small Δ α variations were shown to induce significant changes in Residual Stress Profiles. Compressive Stress near the framework was found to decrease inversely to Δ α . Significance Veneer CTE close to Y-TZP (+0.2 ppm/°C Δ α ) gived the most favorable Stress Profile. Yet, near the framework, Δ α -induced Residual Stress varied inversely to predictions. This could be explained by the hypothesis of structural changes occurrence within the Y-TZP surface. Consequently, the optimum Δα value cannot be determined before understanding Y-TZP's particular behavior when veneered.

  • Residual Stress Profiles in veneering ceramic on Y-TZP, alumina and ZTA frameworks: Measurement by hole-drilling
    Dental Materials, 2013
    Co-Authors: K.a. Fukushima, Michael Sadoun, Paulo Francisco Cesar, Amelie Mainjot
    Abstract:

    Abstract Objectives The Residual Stress Profile developed within the veneering ceramic during the manufacturing process is an important predicting factor in chipping failures, which constitute a well-known problem with yttria-tetragonal-zirconia polycrystal (Y-TZP) based restorations. The objectives of this study are to measure and to compare the Residual Stress Profile in the veneering ceramic layered on three different polycrystalline ceramic framework materials: Y-TZP, alumina polycrystal (AL) and zirconia toughened alumina (ZTA). Methods The Stress Profile was measured with the hole-drilling method in bilayered disk samples of 19 mm diameter with a 0.7 mm thick Y-TZP, AL or ZTA framework and a 1.5 mm thick layer of the corresponding veneering ceramic. Results The AL samples exhibited increasing compressive Stresses with depth, while compressive Stresses switching into interior tensile Stresses were measured in Y-TZP samples. ZTA samples exhibited compressive Stress at the ceramic surface, decreasing with depth up to 0.6 mm from the surface, and then becoming compressive again near the framework. Significance Y-TZP samples exhibited a less favorable Stress Profile than those of AL and ZTA samples. Results support the hypothesis of the occurrence of structural changes within the Y-TZP surface in contact with the veneering ceramic to explain the presence of tensile Stresses. Even if the presence of Y-TZP in the alumina matrix seems to negatively affect the Residual Stress Profiles in ZTA samples in comparison with AL samples, the registered Profiles remain positive in terms of veneer fracture resistance.

  • influence of zirconia framework thickness on Residual Stress Profile in veneering ceramic measurement by hole drilling
    Dental Materials, 2012
    Co-Authors: Amelie Mainjot, Gary S Schajer, Alain Vanheusden, Michael Sadoun
    Abstract:

    Abstract Objectives Framework design is reported to influence chipping in zirconia-based restorations, which is an important cause of failure of such restorations. Residual Stress Profile in the veneering ceramic after the manufacturing process is an important predictive factor of the mechanical behavior of the material. The objective of this study is to investigate the influence of framework thickness on the Stress Profile measured in zirconia-based structures. Methods The Stress Profile was measured with the hole-drilling method in bilayered disc samples of 20 mm diameter with a 1.5 mm thick veneering ceramic layer. Six different framework thicknesses from 0.5 mm to 3 mm were studied. Two different cooling procedures were also investigated. Results Compressive Stresses were observed in the surface, and tensile Stresses in the depth of most of the samples. The slow cooling procedure was found to promote the development of interior tensile Stresses, except for the sample with a 3 mm thick framework. With the tempering procedure, samples with a 1.5 mm thick framework exhibited the most favorable Stress Profile, while thicker and thinner frameworks exhibited respectively in surface or interior tensile Stresses. Significance: The measurements performed highlight the importance of framework thickness, which determine the nature of Stresses and can explain clinical failures encountered, especially with thin frameworks. The adequate ratio between veneering ceramic and zirconia is hard to define, restricting the range of indications of zirconia-based restorations until a better understanding of such a delicate veneering process is achieved.

  • influence of veneer thickness on Residual Stress Profile in veneering ceramic measurement by hole drilling
    Dental Materials, 2012
    Co-Authors: Amelie Mainjot, Gary S Schajer, Alain Vanheusden, Michael Sadoun
    Abstract:

    Abstract Objectives The veneering process of frameworks induces Residual Stresses and can initiate cracks when combined with functional Stresses. The Stress distribution within the veneering ceramic as a function of depth is a key factor influencing failure by chipping. This is a well-known problem with Yttria-tetragonal-zirconia-polycrystal based fixed partial dentures. The objective of this study is to investigate the influence of veneer thickness on the Stress Profile in zirconia- and metal-based structures. Methods The hole-drilling method, often used for engineering measurements, was adapted for use with veneering ceramic. The Stress Profile was measured in bilayered disc samples of 20 mm diameter, with a 1 mm thick zirconia or metal framework. Different veneering ceramic thicknesses were performed: 1 mm, 1.5 mm, 2 mm, 2.5 mm and 3 mm. Results All samples exhibited the same type of Stress vs. depth Profile, starting with compressive at the ceramic surface, decreasing with depth up to 0.5–1.0 mm from the surface, and then becoming compressive again near the framework, except for the 1.5 mm-veneered zirconia samples which exhibited interior tensile Stresses. Stresses in the surface of metal samples were not influenced by veneer thickness. Variation of interior Stresses at 1.2 mm from the surface in function of veneer thickness was inverted for metal and zirconia samples. Significance Veneer thickness influences in an opposite way the Residual Stress Profile in metal- and in zirconia-based structures. A three-step approach and the hypothesis of the crystalline transformation are discussed to explain the less favorable Residual Stress development in zirconia samples.

  • influence of cooling rate on Residual Stress Profile in veneering ceramic measurement by hole drilling
    Dental Materials, 2011
    Co-Authors: Amelie Mainjot, Gary S Schajer, Alain Vanheusden, Michael Sadoun
    Abstract:

    Abstract Objectives The manufacture of dental crowns and bridges generates Residual Stresses within the veneering ceramic and framework during the cooling process. Residual Stress is an important factor that control the mechanical behavior of restorations. Knowing the Stress distribution within the veneering ceramic as a function of depth can help the understanding of failures, particularly chipping, a well-known problem with Yttria-tetragonal-zirconia-polycrystal based fixed partial dentures. The objective of this study is to investigate the cooling rate dependence of the Stress Profile in veneering ceramic layered on metal and zirconia frameworks. Methods The hole-drilling method, often used for engineering measurements, was adapted for use with veneering ceramic. The Stress Profile was measured in bilayered disc samples 20 mm in diameter, with a 0.7 mm thick metal or Yttria-tetragonal-zirconia-polycrystal framework and a 1.5 mm thick veneering ceramic. Three different cooling procedures were investigated. Results The magnitude of the Stresses in the surface of the veneering ceramic was found to increase with cooling rate, while the interior Stresses decreased. At the surface, compressive Stresses were observed in all samples. In the interior, compressive Stresses were observed in metal samples and tensile in zirconia samples. Significance Cooling rate influences the magnitude of Residual Stresses. These can significantly influence the mechanical behavior of metal-and zirconia-based bilayered systems. The framework material influenced the nature of the interior Stresses, with zirconia samples showing a less favorable Stress Profile than metal.

Michael Sadoun - One of the best experts on this subject based on the ideXlab platform.

  • influence of thermal expansion mismatch on Residual Stress Profile in veneering ceramic layered on zirconia measurement by hole drilling
    Dental Materials, 2015
    Co-Authors: Amelie Mainjot, Achref Najjar, Boris D Jakubowiczkohen, Michael Sadoun
    Abstract:

    Abstract Objectives Mismatch in thermal expansion coefficient between core and veneering ceramic (Δ α  =  α core  −  α veneer , ppm/°C) is reported as a crucial parameter influencing veneer fractures with Yttria-tetragonal-zirconia-polycrystal (Y-TZP) prostheses, which still constitutes a misunderstood problem. However, the common positive Δ α concept remains empirical. The objective of this study is to investigate the Δ α dependence of Residual Stress Profiles in veneering ceramic layered on Y-TZP frameworks. Methods The Stress Profile was measured with the hole-drilling method in bilayered disc samples of 20 mm diameter with a 0.7 mm thick Y-TZP framework and a 1.5 mm thick veneer layer. 3 commercial and 4 experimental veneering ceramics ( n  = 3 per group) were used to obtain different Δ α varying from −1.3 ppm/°C to +3.2 ppm/°C, which were determined by dilatometric analyses. Results Veneer fractures were observed in samples with Δ α  ≥ +2.3 or ≤−0.3 ppm/°C. Residual Stress Profiles measured in other groups showed compressive Stresses in the surface, these Stresses decreasing with depth and then becoming more compressive again near the interface. Small Δ α variations were shown to induce significant changes in Residual Stress Profiles. Compressive Stress near the framework was found to decrease inversely to Δ α . Significance Veneer CTE close to Y-TZP (+0.2 ppm/°C Δ α ) gived the most favorable Stress Profile. Yet, near the framework, Δ α -induced Residual Stress varied inversely to predictions. This could be explained by the hypothesis of structural changes occurrence within the Y-TZP surface. Consequently, the optimum Δα value cannot be determined before understanding Y-TZP's particular behavior when veneered.

  • Residual Stress Profiles in veneering ceramic on Y-TZP, alumina and ZTA frameworks: Measurement by hole-drilling
    Dental Materials, 2013
    Co-Authors: K.a. Fukushima, Michael Sadoun, Paulo Francisco Cesar, Amelie Mainjot
    Abstract:

    Abstract Objectives The Residual Stress Profile developed within the veneering ceramic during the manufacturing process is an important predicting factor in chipping failures, which constitute a well-known problem with yttria-tetragonal-zirconia polycrystal (Y-TZP) based restorations. The objectives of this study are to measure and to compare the Residual Stress Profile in the veneering ceramic layered on three different polycrystalline ceramic framework materials: Y-TZP, alumina polycrystal (AL) and zirconia toughened alumina (ZTA). Methods The Stress Profile was measured with the hole-drilling method in bilayered disk samples of 19 mm diameter with a 0.7 mm thick Y-TZP, AL or ZTA framework and a 1.5 mm thick layer of the corresponding veneering ceramic. Results The AL samples exhibited increasing compressive Stresses with depth, while compressive Stresses switching into interior tensile Stresses were measured in Y-TZP samples. ZTA samples exhibited compressive Stress at the ceramic surface, decreasing with depth up to 0.6 mm from the surface, and then becoming compressive again near the framework. Significance Y-TZP samples exhibited a less favorable Stress Profile than those of AL and ZTA samples. Results support the hypothesis of the occurrence of structural changes within the Y-TZP surface in contact with the veneering ceramic to explain the presence of tensile Stresses. Even if the presence of Y-TZP in the alumina matrix seems to negatively affect the Residual Stress Profiles in ZTA samples in comparison with AL samples, the registered Profiles remain positive in terms of veneer fracture resistance.

  • influence of zirconia framework thickness on Residual Stress Profile in veneering ceramic measurement by hole drilling
    Dental Materials, 2012
    Co-Authors: Amelie Mainjot, Gary S Schajer, Alain Vanheusden, Michael Sadoun
    Abstract:

    Abstract Objectives Framework design is reported to influence chipping in zirconia-based restorations, which is an important cause of failure of such restorations. Residual Stress Profile in the veneering ceramic after the manufacturing process is an important predictive factor of the mechanical behavior of the material. The objective of this study is to investigate the influence of framework thickness on the Stress Profile measured in zirconia-based structures. Methods The Stress Profile was measured with the hole-drilling method in bilayered disc samples of 20 mm diameter with a 1.5 mm thick veneering ceramic layer. Six different framework thicknesses from 0.5 mm to 3 mm were studied. Two different cooling procedures were also investigated. Results Compressive Stresses were observed in the surface, and tensile Stresses in the depth of most of the samples. The slow cooling procedure was found to promote the development of interior tensile Stresses, except for the sample with a 3 mm thick framework. With the tempering procedure, samples with a 1.5 mm thick framework exhibited the most favorable Stress Profile, while thicker and thinner frameworks exhibited respectively in surface or interior tensile Stresses. Significance: The measurements performed highlight the importance of framework thickness, which determine the nature of Stresses and can explain clinical failures encountered, especially with thin frameworks. The adequate ratio between veneering ceramic and zirconia is hard to define, restricting the range of indications of zirconia-based restorations until a better understanding of such a delicate veneering process is achieved.

  • influence of veneer thickness on Residual Stress Profile in veneering ceramic measurement by hole drilling
    Dental Materials, 2012
    Co-Authors: Amelie Mainjot, Gary S Schajer, Alain Vanheusden, Michael Sadoun
    Abstract:

    Abstract Objectives The veneering process of frameworks induces Residual Stresses and can initiate cracks when combined with functional Stresses. The Stress distribution within the veneering ceramic as a function of depth is a key factor influencing failure by chipping. This is a well-known problem with Yttria-tetragonal-zirconia-polycrystal based fixed partial dentures. The objective of this study is to investigate the influence of veneer thickness on the Stress Profile in zirconia- and metal-based structures. Methods The hole-drilling method, often used for engineering measurements, was adapted for use with veneering ceramic. The Stress Profile was measured in bilayered disc samples of 20 mm diameter, with a 1 mm thick zirconia or metal framework. Different veneering ceramic thicknesses were performed: 1 mm, 1.5 mm, 2 mm, 2.5 mm and 3 mm. Results All samples exhibited the same type of Stress vs. depth Profile, starting with compressive at the ceramic surface, decreasing with depth up to 0.5–1.0 mm from the surface, and then becoming compressive again near the framework, except for the 1.5 mm-veneered zirconia samples which exhibited interior tensile Stresses. Stresses in the surface of metal samples were not influenced by veneer thickness. Variation of interior Stresses at 1.2 mm from the surface in function of veneer thickness was inverted for metal and zirconia samples. Significance Veneer thickness influences in an opposite way the Residual Stress Profile in metal- and in zirconia-based structures. A three-step approach and the hypothesis of the crystalline transformation are discussed to explain the less favorable Residual Stress development in zirconia samples.

  • influence of cooling rate on Residual Stress Profile in veneering ceramic measurement by hole drilling
    Dental Materials, 2011
    Co-Authors: Amelie Mainjot, Gary S Schajer, Alain Vanheusden, Michael Sadoun
    Abstract:

    Abstract Objectives The manufacture of dental crowns and bridges generates Residual Stresses within the veneering ceramic and framework during the cooling process. Residual Stress is an important factor that control the mechanical behavior of restorations. Knowing the Stress distribution within the veneering ceramic as a function of depth can help the understanding of failures, particularly chipping, a well-known problem with Yttria-tetragonal-zirconia-polycrystal based fixed partial dentures. The objective of this study is to investigate the cooling rate dependence of the Stress Profile in veneering ceramic layered on metal and zirconia frameworks. Methods The hole-drilling method, often used for engineering measurements, was adapted for use with veneering ceramic. The Stress Profile was measured in bilayered disc samples 20 mm in diameter, with a 0.7 mm thick metal or Yttria-tetragonal-zirconia-polycrystal framework and a 1.5 mm thick veneering ceramic. Three different cooling procedures were investigated. Results The magnitude of the Stresses in the surface of the veneering ceramic was found to increase with cooling rate, while the interior Stresses decreased. At the surface, compressive Stresses were observed in all samples. In the interior, compressive Stresses were observed in metal samples and tensile in zirconia samples. Significance Cooling rate influences the magnitude of Residual Stresses. These can significantly influence the mechanical behavior of metal-and zirconia-based bilayered systems. The framework material influenced the nature of the interior Stresses, with zirconia samples showing a less favorable Stress Profile than metal.

Pingsha Dong - One of the best experts on this subject based on the ideXlab platform.

  • A Residual Stress Profile Estimation Method for Narrow Groove Girth Welds
    Volume 1A: Codes and Standards, 2018
    Co-Authors: Shaopin Song, Pingsha Dong
    Abstract:

    A recent comprehensive investigation into Residual Stress distributions in narrow gap welds in pressure vessels and pipe components are presented in this paper, covering component wall thickness from 1” (25.4mm) to 10” (254mm), component radius to wall thickness ratio from 2 to 100, and linear welding heating input from low (300 J/mm) to high (18000 J/mm). By means of a Residual Stress decomposition technique, two key parameters that govern through-thickness Residual Stress distributions in terms of their membrane and bending content have been identified. One is component radius to wall thickness ratio (r/t) and the other is a characteristic heat input density (Q̂) having a unit of J/mm3. With these two parameters, a unified functional form for representing through-thickness Residual Stress Profile in narrow gap welds is proposed for supporting fitness for service assessment, e.g., using f API 579-RP. Its validity is further confirmed by full-blown thermomechanical finite element Residual Stress analyses for a number of selected narrow gap weld cases.

  • a framework for estimating Residual Stress Profile in seam welded pipe and vessel components part i weld region
    International Journal of Pressure Vessels and Piping, 2016
    Co-Authors: Shaopin Song, Pingsha Dong
    Abstract:

    Abstract A recent comprehensive investigation into Residual Stress distributions in pipe and vessel longitudinal seam welds is presented in this paper, covering component wall thickness from 1/4″ (6.35 mm) to 10″ (254 mm), component radius to wall thickness ratio from 2 to 20, and linear welding heat input from low (50 J/mm) to high (6000 J/mm). Through the use of a Residual Stress decomposition technique, two key parameters that govern through-thickness Residual Stress distributions in terms of their membrane and bending content have been identified. One is component radius to wall thickness ratio (r/t) and the other is a characteristic heat input density ( Q ^ ) having a unit of J/mm3. With these two parameters, a unified functional form for estimating through-thickness Residual Stress Profile in seam welded components is proposed in this paper (Part I) for supporting fitness for service assessment for crack-like flaws in weld region. A curved beam bending theory based model is introduced in Part II as a means of analytically describing through-thickness Residual Stress Profile as a function of circumferential position away from the weld region until Residual Stresses become zero. The effectiveness of this proposed framework for achieving Residual Stress Profile estimation within weld region (Part I) for longitudinal seam welds in pressure vessel and piping components has been confirmed by finite element Residual Stress analysis results on a large number of component configurations and different welding conditions.

  • A framework for estimating Residual Stress Profile in seam welded pipe and vessel components Part II: Outside of weld region
    International Journal of Pressure Vessels and Piping, 2016
    Co-Authors: Shaopin Song, Pingsha Dong
    Abstract:

    Abstract A recent comprehensive investigation into Residual Stress distributions in pipe and vessel longitudinal seam welds is presented in this paper, covering component wall thickness from 1/4″ (6.35 mm) to 10″ (254 mm), component radius to wall thickness ratio from 2 to 20, and linear welding heat input from low (50 J/mm) to high (6000 J/mm). Through the use of a Residual Stress decomposition technique, two key parameters that govern through-thickness Residual Stress distributions in terms of their membrane and bending content have been identified. One is component radius to wall thickness ratio ( r / t ) and the other is a characteristic heat input density ( Q ^ ) having a unit of J/mm 3 . With these two parameters, a unified functional form for estimating through-thickness Residual Stress Profile in seam welded components is proposed in this paper (Part I) for supporting fitness for service assessment for crack-like flaws in weld region. A curved beam bending theory based model is introduced in Part II as a means of analytically describing through-thickness Residual Stress Profile as a function of circumferential position away from the weld region until Residual Stresses become zero. The effectiveness of this proposed framework for achieving Residual Stress Profile estimation within weld region (Part I) for longitudinal seam welds in pressure vessel and piping components has been confirmed by finite element Residual Stress analysis results on a large number of component configurations and different welding conditions.

  • an iiw Residual Stress Profile estimation scheme for girth welds in pressure vessel and piping components
    Welding in The World, 2016
    Co-Authors: Pingsha Dong, Shaopin Song
    Abstract:

    Over the years, one major objective of IIW Joint Working Group (JWG) on Residual Stresses and distortion prediction (RSDP) has been the development of consistent Residual Stress Profiles for supporting fitness-for-service assessment of welded components. As a result of the JWG activities and further in-depth investigations, this paper presents a major development on a novel full-field Residual Stress estimation scheme that can be used for describing through-thickness Residual Stress Profiles not only within a weld region, but also at any location away from a weld in pressure vessel and piping components. Within weld region, a systematic parametric finite element analysis is used to establish key parameters that govern through-thickness Residual Stress distribution characteristics by introducing membrane, bending, and self-equilibrating based decomposition technique. Away from weld region, a shell theory based method is developed for describing through-thickness Residual Stress distribution at any distance away from weld toe. This paper presents detailed results for single “V” joint preparation with pipe wall thickness varying from 6.25 to 250 mm and wall thickness to pipe radius ratio (r/t) varying from 2 to 100. The Residual Stress estimation method can be applied for double V and narrow groove joint preparations for girth welded components since all three joint preparations have been shown to follow a similar functional form to that seen in single V joint preparation.

  • analysis of Residual Stresses in pipe seam welds and a proposed Residual Stress Profile estimation method
    ASME 2015 Pressure Vessels and Piping Conference PVP 2015, 2015
    Co-Authors: Shaopin Song, Pingsha Dong
    Abstract:

    A recent comprehensive investigation into Residual Stress distributions in pipe and vessel longitudinal seam welds is presented in this paper, covering component wall thickness from 1/4” (6.35mm) to 10” (254mm), component radius to wall thickness ratio from 2 to 10, and linear welding heating input from low (50 J/mm) to high (6000 J/mm). Through the use of a Residual Stress decomposition technique, two key parameters that govern through-thickness Residual Stress distributions in terms of their membrane and bending content have been identified. One is component radius to wall thickness ratio (r/t) and the other is a characteristic heat input density (Q) having a unit of J/mm3. With these two parameters, a unified functional form for representing through-thickness Residual Stress Profile behaviors in seam welds is proposed along with its solution procedure for applications in weld region. The simplicity of the proposed Residual Stress Profile estimation scheme in functional form and demonstrated applicability for a wide range of r/t and Q provides an effective framework for generating Residual Stress Profile information for supporting defect assessment procedures in FFS codes and standards.Copyright © 2015 by ASME

Shaopin Song - One of the best experts on this subject based on the ideXlab platform.

  • A Residual Stress Profile Estimation Method for Narrow Groove Girth Welds
    Volume 1A: Codes and Standards, 2018
    Co-Authors: Shaopin Song, Pingsha Dong
    Abstract:

    A recent comprehensive investigation into Residual Stress distributions in narrow gap welds in pressure vessels and pipe components are presented in this paper, covering component wall thickness from 1” (25.4mm) to 10” (254mm), component radius to wall thickness ratio from 2 to 100, and linear welding heating input from low (300 J/mm) to high (18000 J/mm). By means of a Residual Stress decomposition technique, two key parameters that govern through-thickness Residual Stress distributions in terms of their membrane and bending content have been identified. One is component radius to wall thickness ratio (r/t) and the other is a characteristic heat input density (Q̂) having a unit of J/mm3. With these two parameters, a unified functional form for representing through-thickness Residual Stress Profile in narrow gap welds is proposed for supporting fitness for service assessment, e.g., using f API 579-RP. Its validity is further confirmed by full-blown thermomechanical finite element Residual Stress analyses for a number of selected narrow gap weld cases.

  • a framework for estimating Residual Stress Profile in seam welded pipe and vessel components part i weld region
    International Journal of Pressure Vessels and Piping, 2016
    Co-Authors: Shaopin Song, Pingsha Dong
    Abstract:

    Abstract A recent comprehensive investigation into Residual Stress distributions in pipe and vessel longitudinal seam welds is presented in this paper, covering component wall thickness from 1/4″ (6.35 mm) to 10″ (254 mm), component radius to wall thickness ratio from 2 to 20, and linear welding heat input from low (50 J/mm) to high (6000 J/mm). Through the use of a Residual Stress decomposition technique, two key parameters that govern through-thickness Residual Stress distributions in terms of their membrane and bending content have been identified. One is component radius to wall thickness ratio (r/t) and the other is a characteristic heat input density ( Q ^ ) having a unit of J/mm3. With these two parameters, a unified functional form for estimating through-thickness Residual Stress Profile in seam welded components is proposed in this paper (Part I) for supporting fitness for service assessment for crack-like flaws in weld region. A curved beam bending theory based model is introduced in Part II as a means of analytically describing through-thickness Residual Stress Profile as a function of circumferential position away from the weld region until Residual Stresses become zero. The effectiveness of this proposed framework for achieving Residual Stress Profile estimation within weld region (Part I) for longitudinal seam welds in pressure vessel and piping components has been confirmed by finite element Residual Stress analysis results on a large number of component configurations and different welding conditions.

  • A framework for estimating Residual Stress Profile in seam welded pipe and vessel components Part II: Outside of weld region
    International Journal of Pressure Vessels and Piping, 2016
    Co-Authors: Shaopin Song, Pingsha Dong
    Abstract:

    Abstract A recent comprehensive investigation into Residual Stress distributions in pipe and vessel longitudinal seam welds is presented in this paper, covering component wall thickness from 1/4″ (6.35 mm) to 10″ (254 mm), component radius to wall thickness ratio from 2 to 20, and linear welding heat input from low (50 J/mm) to high (6000 J/mm). Through the use of a Residual Stress decomposition technique, two key parameters that govern through-thickness Residual Stress distributions in terms of their membrane and bending content have been identified. One is component radius to wall thickness ratio ( r / t ) and the other is a characteristic heat input density ( Q ^ ) having a unit of J/mm 3 . With these two parameters, a unified functional form for estimating through-thickness Residual Stress Profile in seam welded components is proposed in this paper (Part I) for supporting fitness for service assessment for crack-like flaws in weld region. A curved beam bending theory based model is introduced in Part II as a means of analytically describing through-thickness Residual Stress Profile as a function of circumferential position away from the weld region until Residual Stresses become zero. The effectiveness of this proposed framework for achieving Residual Stress Profile estimation within weld region (Part I) for longitudinal seam welds in pressure vessel and piping components has been confirmed by finite element Residual Stress analysis results on a large number of component configurations and different welding conditions.

  • an iiw Residual Stress Profile estimation scheme for girth welds in pressure vessel and piping components
    Welding in The World, 2016
    Co-Authors: Pingsha Dong, Shaopin Song
    Abstract:

    Over the years, one major objective of IIW Joint Working Group (JWG) on Residual Stresses and distortion prediction (RSDP) has been the development of consistent Residual Stress Profiles for supporting fitness-for-service assessment of welded components. As a result of the JWG activities and further in-depth investigations, this paper presents a major development on a novel full-field Residual Stress estimation scheme that can be used for describing through-thickness Residual Stress Profiles not only within a weld region, but also at any location away from a weld in pressure vessel and piping components. Within weld region, a systematic parametric finite element analysis is used to establish key parameters that govern through-thickness Residual Stress distribution characteristics by introducing membrane, bending, and self-equilibrating based decomposition technique. Away from weld region, a shell theory based method is developed for describing through-thickness Residual Stress distribution at any distance away from weld toe. This paper presents detailed results for single “V” joint preparation with pipe wall thickness varying from 6.25 to 250 mm and wall thickness to pipe radius ratio (r/t) varying from 2 to 100. The Residual Stress estimation method can be applied for double V and narrow groove joint preparations for girth welded components since all three joint preparations have been shown to follow a similar functional form to that seen in single V joint preparation.

  • analysis of Residual Stresses in pipe seam welds and a proposed Residual Stress Profile estimation method
    ASME 2015 Pressure Vessels and Piping Conference PVP 2015, 2015
    Co-Authors: Shaopin Song, Pingsha Dong
    Abstract:

    A recent comprehensive investigation into Residual Stress distributions in pipe and vessel longitudinal seam welds is presented in this paper, covering component wall thickness from 1/4” (6.35mm) to 10” (254mm), component radius to wall thickness ratio from 2 to 10, and linear welding heating input from low (50 J/mm) to high (6000 J/mm). Through the use of a Residual Stress decomposition technique, two key parameters that govern through-thickness Residual Stress distributions in terms of their membrane and bending content have been identified. One is component radius to wall thickness ratio (r/t) and the other is a characteristic heat input density (Q) having a unit of J/mm3. With these two parameters, a unified functional form for representing through-thickness Residual Stress Profile behaviors in seam welds is proposed along with its solution procedure for applications in weld region. The simplicity of the proposed Residual Stress Profile estimation scheme in functional form and demonstrated applicability for a wide range of r/t and Q provides an effective framework for generating Residual Stress Profile information for supporting defect assessment procedures in FFS codes and standards.Copyright © 2015 by ASME

Vincenzo M Sglavo - One of the best experts on this subject based on the ideXlab platform.

  • nondestructive measurement of the Residual Stress Profile in ceramic laminates
    Journal of the American Ceramic Society, 2008
    Co-Authors: Matteo Leoni, Vincenzo M Sglavo, Massimo Bertoldi, Matteo Ortolani, P Scardi
    Abstract:

    Millimeter-thick symmetric ceramic laminates, designed to possess a specific through-thickness Residual Stress Profile, were produced by tape casting from blends of alumina, zirconia, and mullite powders. The Residual Stress Profile was checked nondestructively by X-ray energy-dispersive diffraction using synchrotron white-beam radiation. Measurement of the average Stress on very small volumes (ca. 10 μm along the specimen thickness) provided results in good agreement with the design data. Moreover, the possibility of independently measuring each crystalline phase composing the laminate allowed inferences to be made on Stress partition and grain–grain coupling in the laminas.

  • ceramic laminates with high mechanical reliability by design
    Ceramic engineering and science proceedings, 2008
    Co-Authors: Vincenzo M Sglavo, Massimo Bertoldi
    Abstract:

    A procedure for designing innovative ceramic laminates with high mechanical performances is proposed in this work. A fracture mechanics approach has been considered to define the stacking sequence, thickness and composition of the different laminae on the basis of the requested strength and of the defect size distribution. Once the different laminae are stacked together a Residual Stress Profile is generated upon cooling after sintering because of the differential thermal expansion coefficient. Such Residual Stress Profile is conceived in order to allow stable growth of surface defects upon bending and guarantee limited strength scatter. As an example, the proposed approach is then used to design and produce a ceramic laminate in the alumina-mullite system.

  • Design and production of ceramic laminates with high mechanical reliability
    Composites Part B-engineering, 2006
    Co-Authors: Vincenzo M Sglavo, Massimo Bertoldi
    Abstract:

    Abstract A procedure for designing innovative ceramic laminates characterized by high mechanical reliability is proposed in this work. A fracture mechanics approach has been considered to define the stacking sequence, thickness and composition of the different laminae on the basis of the requested strength and of the defect size distribution. Once the different laminae are stacked together a Residual Stress Profile is generated upon cooling after sintering because of the differential thermal expansion coefficient. Such Residual Stress Profile is conceived in order to allow stable growth of surface defects upon bending and guarantee limited strength scatter. As an example, the proposed approach is used to design and produce ceramic laminates in the alumina–zirconia and alumina–mullite system. Mechanical performances of the produced materials are discussed in terms of the generated Residual Stress Profile and compared to parent monolithic ceramics.

  • procedure for Residual Stress Profile determination by curvature measurements
    Mechanics of Materials, 2005
    Co-Authors: Vincenzo M Sglavo, Marco Bonafini, Andrea Prezzi
    Abstract:

    A procedure is presented for the measurement of Residual Stress Profile in regular geometry bodies such as plates and disks. The experimental work is based on the sole measurement of the sample curvature deriving from progressively etching one of its surfaces. A relationship is obtained to correlate curvature data as function of etching depth to the original Residual Stress Profile. The sensitivity of the method and the influence of possible experimental errors are analyzed. The technique is then applied to strengthened glass samples produced by both thermal tempering and ion exchange and obtained results are compared to data obtained by available alternative technique to demonstrate the validity of the proposed approach.

  • Procedure for Residual Stress Profile determination by curvature measurements
    Mechanics of Materials, 2005
    Co-Authors: Vincenzo M Sglavo, Marco Bonafini, Andrea Prezzi
    Abstract:

    A procedure is presented for the measurement of Residual Stress Profile in regular geometry bodies such as plates and disks. The experimental work is based on the sole measurement of the sample curvature deriving from progressively etching one of its surfaces. A relationship is obtained to correlate curvature data as function of etching depth to the original Residual Stress Profile. The sensitivity of the method and the influence of possible experimental errors are analyzed. The technique is then applied to strengthened glass samples produced by both thermal tempering and ion exchange and obtained results are compared to data obtained by available alternative technique to demonstrate the validity of the proposed approach. © 2004 Elsevier Ltd. All rights resesrved.