The Experts below are selected from a list of 399 Experts worldwide ranked by ideXlab platform

Chwee Teck Lim - One of the best experts on this subject based on the ideXlab platform.

  • modulus grading versus geometrical grading of composite adherends in single lap bonded joints
    Composite Structures, 2003
    Co-Authors: J N Boss, V K Ganesh, Chwee Teck Lim
    Abstract:

    The behavior of single-lap adhesive bonded joints with modulus and geometrically graded adherends was examined. The modulus grading of the adherend was provided by continuously varying the Braid Angle and geometrical grading provided by varying the adherend thickness in the overlap region. The peak stress distribution and transverse deformation at the adhesive mid-thickness calculated using finite element method was used to compare the performance of modulus grading and geometrical grading. It was noticed that for certain cases, modulus grading provides reduced stress levels compared to geometrical grading. In certain other cases they demonstrate benefits similar to geometrically graded adherends. In case of shear stress reduction, modulus grading provided better performance; however, it is possible to combine modulus and geometrical grading to evolve an overall better performing single-lap bonded joints.

V K Ganesh - One of the best experts on this subject based on the ideXlab platform.

  • modulus grading versus geometrical grading of composite adherends in single lap bonded joints
    Composite Structures, 2003
    Co-Authors: J N Boss, V K Ganesh, Chwee Teck Lim
    Abstract:

    The behavior of single-lap adhesive bonded joints with modulus and geometrically graded adherends was examined. The modulus grading of the adherend was provided by continuously varying the Braid Angle and geometrical grading provided by varying the adherend thickness in the overlap region. The peak stress distribution and transverse deformation at the adhesive mid-thickness calculated using finite element method was used to compare the performance of modulus grading and geometrical grading. It was noticed that for certain cases, modulus grading provides reduced stress levels compared to geometrical grading. In certain other cases they demonstrate benefits similar to geometrically graded adherends. In case of shear stress reduction, modulus grading provided better performance; however, it is possible to combine modulus and geometrical grading to evolve an overall better performing single-lap bonded joints.

  • modulus graded composite adherends for single lap bonded joints
    Journal of Composite Materials, 2002
    Co-Authors: V K Ganesh, T S Choo
    Abstract:

    The effect of spatial grading of adherend elastic modulus on the peak stress and stress distribution in the single-lap bonded joint is studied. Single-lap joint with various modulus grading profiles were studied and the results compared with the traditional uniform modulus adherends using linear elastic finite element analysis. Braided preform with continuously varying Braid Angle was fabricated and the variation of the Braid Angle measured to realistically evaluate the performance of adherend modulus grading in single-lap bonded joint. The peak stress, stress distribution and transverse displacement at the adhesive mid-thickness were used to compare between the different adherend modulusgrading. The maximum shear stress reduced by about 20% and the shear stress was more uniformly distributed in the adhesive for an actual case of adherend modulus grading. It was also noticed that the joint rotation wasminimum for thisactual case of adherend grading.

J N Boss - One of the best experts on this subject based on the ideXlab platform.

  • modulus grading versus geometrical grading of composite adherends in single lap bonded joints
    Composite Structures, 2003
    Co-Authors: J N Boss, V K Ganesh, Chwee Teck Lim
    Abstract:

    The behavior of single-lap adhesive bonded joints with modulus and geometrically graded adherends was examined. The modulus grading of the adherend was provided by continuously varying the Braid Angle and geometrical grading provided by varying the adherend thickness in the overlap region. The peak stress distribution and transverse deformation at the adhesive mid-thickness calculated using finite element method was used to compare the performance of modulus grading and geometrical grading. It was noticed that for certain cases, modulus grading provides reduced stress levels compared to geometrical grading. In certain other cases they demonstrate benefits similar to geometrically graded adherends. In case of shear stress reduction, modulus grading provided better performance; however, it is possible to combine modulus and geometrical grading to evolve an overall better performing single-lap bonded joints.

Remko Akkerman - One of the best experts on this subject based on the ideXlab platform.

  • A yarn interaction model for circular Braiding
    Composites Part A-applied Science and Manufacturing, 2016
    Co-Authors: Johan H. Van Ravenhorst, Remko Akkerman
    Abstract:

    Machine control data for the automation of the circular Braiding process has been generated using previously published mathematical models that neglect yarn interaction. This resulted in a significant deviation from the required Braid Angle at mandrel cross-sectional changes, likely caused by an incorrect convergence zone length, in turn caused by this neglect. Therefore the objective is to use a new model that includes the yarn interaction, assuming an axisymmetrical biaxial process with a cylindrical mandrel and Coulomb friction. Experimental validation with carbon yarns and a 144 carrier machine confirms a convergence zone length decrease of 25% with respect to a model without yarn interaction for the case analyzed, matching the model prediction using a coefficient of friction of around 0.3.

  • circular Braiding take up speed generation using inverse kinematics
    Composites Part A-applied Science and Manufacturing, 2014
    Co-Authors: Johan H. Van Ravenhorst, Remko Akkerman
    Abstract:

    Circular overBraiding of composite preforms on complex mandrels currently lacks automatic generation of machine control data. To solve this limitation, an inverse kinematics-based procedure was designed and implemented for circular Braiding machines with optional guide rings, resulting in a take-up speed profile for a given Braid Angle distribution on mandrels with complex 3D shapes including non-axisymmetric, optionally eccentric cross-sections that can vary in shape and size along an optionally curved mandrel centerline, allowing a curved machine movement. This procedure reduces the problem size, resulting in a short computation time, fit for CAE process chain integration. Numerical control data was generated for a complex mandrel with a specified Braid Angle and a triaxial Braid. A simulation using this control data yields a Braid Angle that deviates a few degrees from the specified Braid Angle. The simulation was validated experimentally, using the generated instructions to control the Braiding machine. This showed a deviation from the simulated Braid Angle of 3 degrees in the centered, non-tapered mandrel regions, up to 10 degrees in tapered regions and an experimental scatter of 7 degrees. The deviation is mainly attributed to the neglect of yarn interaction and guide ring contact friction in the model, leading to an incorrectly modeled convergence zone length.

  • Circular Braiding Process Simulation for a Pressure Vessel
    Volume 6A: Materials and Fabrication, 2014
    Co-Authors: Johan H. Van Ravenhorst, Remko Akkerman
    Abstract:

    Pressure vessel manufacturing is currently dominated by the filament winding process. When higher production rates are required, circular Braiding can be considered as an alternative because hundreds of yarns are deposited simultaneously from interlacing spools. The process has a high repeatability and is suited for automated series production, as is currently shown with the production of a-pillars and rockers in the automotive industry. Important manufacturing constraints related to the overBraiding of cylindrical pressure vessels are to avoid excessive jamming of the Braid, typically occurring at a small mandrel radius, and to achieve a 100% cover factor at the largest mandrel diameter. In this paper, design guidelines for Braiding of cylindrical pressure vessels are proposed. It is shown that a proper choice of the yarn cross-sectional area size and of yarn width-to-thickness aspect ratio can improve the design feasibility, but an adjustment of the Braid Angle can be required as well.Copyright © 2014 by ASME

  • optimisation of the circular Braiding process
    11th International Conference on Textile Composites Home 2013, 2013
    Co-Authors: J.h. Van Ravenhorst, Remko Akkerman
    Abstract:

    A geometry-based procedure for circular Braiding take-up speed optimization is proposed for arbitrary mandrels. The resulting virtual Braid Angle deviates a few degrees from the required Braid Angle while the experimental error is up to 10 degrees in tapered regions, mainly caused by the neglect of yarn interaction in the model.

  • Braiding take-up speed optimization - case studies
    2013
    Co-Authors: J.h. Van Ravenhorst, Bert Rietman, Remko Akkerman
    Abstract:

    Circular Braiding is a composite material manufacturing process for production of bi- and triaxial tubular preforms that are usually impregnated and cured using Resin Transfer Moulding. The process currently lacks automatic generation of optimum machine control data. Helping to solve this problem, a newly developed geometry-based procedure for take-up speed optimization is applied to various complex mandrel shapes to assess its strengths and weaknesses. As a result, the error of the virtual Braid Angle could be reduced to a few degrees. However, in order to assess the validity of the generated process settings, it is recommended to take into account the manufacturing constraints regarding the prevention of yarn slack and fiber slip.

Johan H. Van Ravenhorst - One of the best experts on this subject based on the ideXlab platform.

  • A yarn interaction model for circular Braiding
    Composites Part A-applied Science and Manufacturing, 2016
    Co-Authors: Johan H. Van Ravenhorst, Remko Akkerman
    Abstract:

    Machine control data for the automation of the circular Braiding process has been generated using previously published mathematical models that neglect yarn interaction. This resulted in a significant deviation from the required Braid Angle at mandrel cross-sectional changes, likely caused by an incorrect convergence zone length, in turn caused by this neglect. Therefore the objective is to use a new model that includes the yarn interaction, assuming an axisymmetrical biaxial process with a cylindrical mandrel and Coulomb friction. Experimental validation with carbon yarns and a 144 carrier machine confirms a convergence zone length decrease of 25% with respect to a model without yarn interaction for the case analyzed, matching the model prediction using a coefficient of friction of around 0.3.

  • circular Braiding take up speed generation using inverse kinematics
    Composites Part A-applied Science and Manufacturing, 2014
    Co-Authors: Johan H. Van Ravenhorst, Remko Akkerman
    Abstract:

    Circular overBraiding of composite preforms on complex mandrels currently lacks automatic generation of machine control data. To solve this limitation, an inverse kinematics-based procedure was designed and implemented for circular Braiding machines with optional guide rings, resulting in a take-up speed profile for a given Braid Angle distribution on mandrels with complex 3D shapes including non-axisymmetric, optionally eccentric cross-sections that can vary in shape and size along an optionally curved mandrel centerline, allowing a curved machine movement. This procedure reduces the problem size, resulting in a short computation time, fit for CAE process chain integration. Numerical control data was generated for a complex mandrel with a specified Braid Angle and a triaxial Braid. A simulation using this control data yields a Braid Angle that deviates a few degrees from the specified Braid Angle. The simulation was validated experimentally, using the generated instructions to control the Braiding machine. This showed a deviation from the simulated Braid Angle of 3 degrees in the centered, non-tapered mandrel regions, up to 10 degrees in tapered regions and an experimental scatter of 7 degrees. The deviation is mainly attributed to the neglect of yarn interaction and guide ring contact friction in the model, leading to an incorrectly modeled convergence zone length.

  • Circular Braiding Process Simulation for a Pressure Vessel
    Volume 6A: Materials and Fabrication, 2014
    Co-Authors: Johan H. Van Ravenhorst, Remko Akkerman
    Abstract:

    Pressure vessel manufacturing is currently dominated by the filament winding process. When higher production rates are required, circular Braiding can be considered as an alternative because hundreds of yarns are deposited simultaneously from interlacing spools. The process has a high repeatability and is suited for automated series production, as is currently shown with the production of a-pillars and rockers in the automotive industry. Important manufacturing constraints related to the overBraiding of cylindrical pressure vessels are to avoid excessive jamming of the Braid, typically occurring at a small mandrel radius, and to achieve a 100% cover factor at the largest mandrel diameter. In this paper, design guidelines for Braiding of cylindrical pressure vessels are proposed. It is shown that a proper choice of the yarn cross-sectional area size and of yarn width-to-thickness aspect ratio can improve the design feasibility, but an adjustment of the Braid Angle can be required as well.Copyright © 2014 by ASME