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M A Mccarthy - One of the best experts on this subject based on the ideXlab platform.

  • stress analysis of single Bolt single lap countersunk composite joints with variable Bolt Hole clearance
    Composite Structures, 2012
    Co-Authors: Brian Egan, M A Mccarthy, C T Mccarthy, R M Frizzell
    Abstract:

    Abstract Single-lap, carbon–epoxy joints with countersunk fasteners were modelled using the nonlinear finite element code Abaqus. A highly-detailed analysis of the stress distribution at the countersunk Hole boundary is provided. Bolt-Hole clearance, which arises due to limitations in manufacturing capabilities, is modelled extensively. Clearance levels both inside and outside typical aerospace fitting tolerances are studied and the finite element model is validated with experimental data. Plots of radial stress in each ply of the countersunk laminate show the load transfer to be severely localised, with only a few plies bearing the majority of the load. The inclusion of clearance in the model was shown to result in far higher radial stresses compared to those in the neat-fit joint model. An associated loss in joint stiffness of more than 10% was recorded for the highest clearance considered (240 μm). Finally compressive through-thickness stresses are shown to be present at the damageable region of the countersunk Hole, and increase with Bolt-Hole clearance. These compressive stresses, which are an indicator of lateral constraint, are seen to suppress “brooming” failure in the countersunk laminate.

  • a simple method for determining the effects of Bolt Hole clearance on load distribution in single column multi Bolt composite joints
    Composite Structures, 2006
    Co-Authors: M A Mccarthy, C T Mccarthy, G S Padhi
    Abstract:

    Abstract In this paper, a simplified method for determining the effects of Bolt–Hole clearance on the load distribution in composite multi-Bolt joints is presented. The method is applicable to joints with a single column of Bolts and is an extension of a previous method which did not include clearance effects. It can be applied to both single-lap and double-lap joints. The method is validated against three-dimensional finite element models, and some examples of different clearance cases are shown. It is shown that even small amounts of clearance can significantly alter the load distribution in the joint. Finally the method is used in a parameter study to examine the effects of various joint parameters on load distribution.

  • three dimensional finite element analysis of single Bolt single lap composite Bolted joints part ii effects of Bolt Hole clearance
    Composite Structures, 2005
    Co-Authors: C T Mccarthy, M A Mccarthy
    Abstract:

    Abstract Three-dimensional finite element models have been developed to study the effects of Bolt-Hole clearance on the mechanical behaviour of Bolted composite (graphite/epoxy) joints. In Part I of this two-part paper, the model was developed in the finite element code MSC.Marc and validated against experiments and other finite element solutions. In this second part of the paper, results from the model showing the effects of clearance in single-lap, single-Bolt joints are presented and compared with experimental results. Both quasi-isotropic and zero-dominated lay-ups are studied. It is shown that increased clearance leads to increased Bolt rotation, decreased Bolt-Hole contact area, and decreased joint stiffness. In single-lap joints, clearance is shown to cause three-dimensional variations in the stress distribution in the laminate, and these variations are also dependent on the lay-up; the radial and tangential stresses in each ply are shown to illustrate this point. Finally, a prediction of the failure onset load using Hashin’s failure criteria is given and the results are compared with experimental results.

  • an experimental study of Bolt Hole clearance effects in double lap multi Bolt composite joints
    Composite Structures, 2005
    Co-Authors: V P Lawlor, M A Mccarthy, W F Stanley
    Abstract:

    Abstract An experimental study on the effects of variable Bolt–Hole clearance in double-lap, multi-Bolt joints is presented. Joints with different clearances in each Hole have been tested and the effects on load distribution, quasi-static strength, fatigue life and failure modes are reported. Strain gauges have been used for measuring load distribution and specialised jigs have been used for positioning the Bolts in the Holes and drilling the joints. The clearances examined ranged from neat-fit to clearances slightly larger than those allowed in the aircraft industry. Clearance has been found to have major effects on the load distribution; no effect on ultimate quasi-static strength but significant effect on failure initiation load; and quite significant effects on fatigue life.

  • An experimental study of Bolt–Hole clearance effects in double-lap, multi-Bolt composite joints
    Composite Structures, 2005
    Co-Authors: V P Lawlor, M A Mccarthy, W F Stanley
    Abstract:

    Abstract An experimental study on the effects of variable Bolt–Hole clearance in double-lap, multi-Bolt joints is presented. Joints with different clearances in each Hole have been tested and the effects on load distribution, quasi-static strength, fatigue life and failure modes are reported. Strain gauges have been used for measuring load distribution and specialised jigs have been used for positioning the Bolts in the Holes and drilling the joints. The clearances examined ranged from neat-fit to clearances slightly larger than those allowed in the aircraft industry. Clearance has been found to have major effects on the load distribution; no effect on ultimate quasi-static strength but significant effect on failure initiation load; and quite significant effects on fatigue life.

C T Mccarthy - One of the best experts on this subject based on the ideXlab platform.

  • stress analysis of single Bolt single lap countersunk composite joints with variable Bolt Hole clearance
    Composite Structures, 2012
    Co-Authors: Brian Egan, M A Mccarthy, C T Mccarthy, R M Frizzell
    Abstract:

    Abstract Single-lap, carbon–epoxy joints with countersunk fasteners were modelled using the nonlinear finite element code Abaqus. A highly-detailed analysis of the stress distribution at the countersunk Hole boundary is provided. Bolt-Hole clearance, which arises due to limitations in manufacturing capabilities, is modelled extensively. Clearance levels both inside and outside typical aerospace fitting tolerances are studied and the finite element model is validated with experimental data. Plots of radial stress in each ply of the countersunk laminate show the load transfer to be severely localised, with only a few plies bearing the majority of the load. The inclusion of clearance in the model was shown to result in far higher radial stresses compared to those in the neat-fit joint model. An associated loss in joint stiffness of more than 10% was recorded for the highest clearance considered (240 μm). Finally compressive through-thickness stresses are shown to be present at the damageable region of the countersunk Hole, and increase with Bolt-Hole clearance. These compressive stresses, which are an indicator of lateral constraint, are seen to suppress “brooming” failure in the countersunk laminate.

  • a simple method for determining the effects of Bolt Hole clearance on load distribution in single column multi Bolt composite joints
    Composite Structures, 2006
    Co-Authors: M A Mccarthy, C T Mccarthy, G S Padhi
    Abstract:

    Abstract In this paper, a simplified method for determining the effects of Bolt–Hole clearance on the load distribution in composite multi-Bolt joints is presented. The method is applicable to joints with a single column of Bolts and is an extension of a previous method which did not include clearance effects. It can be applied to both single-lap and double-lap joints. The method is validated against three-dimensional finite element models, and some examples of different clearance cases are shown. It is shown that even small amounts of clearance can significantly alter the load distribution in the joint. Finally the method is used in a parameter study to examine the effects of various joint parameters on load distribution.

  • three dimensional finite element analysis of single Bolt single lap composite Bolted joints part ii effects of Bolt Hole clearance
    Composite Structures, 2005
    Co-Authors: C T Mccarthy, M A Mccarthy
    Abstract:

    Abstract Three-dimensional finite element models have been developed to study the effects of Bolt-Hole clearance on the mechanical behaviour of Bolted composite (graphite/epoxy) joints. In Part I of this two-part paper, the model was developed in the finite element code MSC.Marc and validated against experiments and other finite element solutions. In this second part of the paper, results from the model showing the effects of clearance in single-lap, single-Bolt joints are presented and compared with experimental results. Both quasi-isotropic and zero-dominated lay-ups are studied. It is shown that increased clearance leads to increased Bolt rotation, decreased Bolt-Hole contact area, and decreased joint stiffness. In single-lap joints, clearance is shown to cause three-dimensional variations in the stress distribution in the laminate, and these variations are also dependent on the lay-up; the radial and tangential stresses in each ply are shown to illustrate this point. Finally, a prediction of the failure onset load using Hashin’s failure criteria is given and the results are compared with experimental results.

  • progressive damage analysis of multi Bolt composite joints with variable Bolt Hole clearances
    Composites Part B-engineering, 2005
    Co-Authors: C T Mccarthy, M A Mccarthy, V P Lawlor
    Abstract:

    Abstract A 3D progressive damage finite element model of multi-Bolt, double-lap composite joints is developed in the non-linear finite element code ABAQUS. The model is validated by comparing load–displacement characteristics and surface strains to experimental results. A study is then performed of the effects of variable Bolt–Hole clearance with results compared to experiments in which Bolt loads were measured in joints loaded to ultimate failure. It is shown that clearance can cause major changes in the load distribution and damage mechanisms in the joint. It can also lead to a significant reduction in the load at which initial failure (due to bearing at one of the Holes) occurs, making it an important variable to consider in the limit load design of aircraft. Unlike previous methods, the method presented here is capable of correctly accounting for bearing and bypass stresses, in the presence of damaged material properties, as well as the load re-distribution that occurs after bearing failure at one or more Holes.

  • Bolt Hole clearance effects and strength criteria in single Bolt single lap composite Bolted joints
    Composites Science and Technology, 2002
    Co-Authors: M A Mccarthy, V P Lawlor, W F Stanley, C T Mccarthy
    Abstract:

    Abstract Effects of Bolt-Hole clearance on the stiffness and strength of composite Bolted joints were investigated. The configuration studied was single-lap, single-Bolt. Four different clearances were obtained using variable size reamers, ranging from neat-fit to 240 μm. The specimens were manufactured in accordance with ASTM standard D5961/D5961 M-96, from graphite/epoxy HTA/6376, with quasi-isotropic and zero-dominated lay-ups. Both protruding head and countersunk Bolts were used, with two different applied torque levels. Specimen dimensions were chosen to obtain bearing as the primary mode of failure, with ultimate failure being mostly through Bolt failure. Joint stiffness, 2% offset bearing strength, ultimate bearing strength and ultimate bearing strain were obtained according to the Standard. In addition, an alternative definition of strength was derived, which has some advantages over the offset method, and the results were evaluated according to this definition. Increasing clearance was found to result in reduced joint stiffness and increased ultimate strain in all tested configurations. Finger-tight joints with protruding head Bolts showed a link between clearance and strength, but countersunk and torqued joints did not. A delay in load take-up also occurred with the higher clearance joints, which has implications for load distributions in multi-Bolt joints.

Jung-min Park - One of the best experts on this subject based on the ideXlab platform.

  • Bolting Cabin Assistance System Using a Sensor Network
    International Journal of Advanced Robotic Systems, 2012
    Co-Authors: Yung Hak Mo, Yungeun Choe, Jung-min Park
    Abstract:

    The Bolting cabin assistance system prevents operators from facing dangerous situations. This system consists of a Bolting robot control system and a top view supervisory system. In order to control the Bolting robot, circular Hough transforms and fuzzy reasoning are used. First, the circular Hough transform roughly estimates the location of the Bolt Hole. After that, errors of estimation are compensated for using fuzzy reasoning. In order to track a Bolt Hole, a region of interest (ROI) is used. By setting the region in which to search for a Bolt Hole, the algorithm tracks the location of the Bolt Hole. In order to choose an ROI, a template-based matching algorithm is used. In order to make the top view supervisory system, four cameras are installed at the left, right, front and back of the robot. The four individual images from the various cameras are combined to make the top view image after correcting for distortion.

  • Cognition system of Bolt Hole using template matching
    28th International Symposium on Automation and Robotics in Construction (ISARC 2011), 2011
    Co-Authors: Gwan Ryong Baek, Yung Hak Mo, Jae Sik Jeong, Jung-min Park
    Abstract:

    In the construction field, the Bolting robot provides convenience and reduces a process time of assembling steel frames. When assembling steel frames, the Bolting robot finds a Bolt Hole with the help of camera. If the light conditions are either too bright or too dark, however, it is hard to find a Bolt Hole in the input image because the contrast between Bolt Hole and background is vague. In order to improve detection accuracy in such environment, this paper proposes the image processing algorithm using template matching (TM). First, the input image is converted from RGB to YCbCr in order to reduce influence of shadow. Then we separate Y channel of image in darkness or extract edges from Cb and Cr channel of image in brightness. Template image is created with the radius which can be calculated with the distance to a steel frame. We used TM to create the normalized cross correlation (NCC) image which shows correlation between processed image and template. Finally, Bolt Holes are extracted from the high-correlation part of NCC image. Experimental results show that the proposed method is robust to detect Bolt Holes under various illumination conditions.

  • Robust detection system of a Bolt Hole using template matching and feature based matching
    2011 11th International Conference on Control Automation and Systems, 2011
    Co-Authors: Yung Hak Mo, Jung-min Park
    Abstract:

    This paper suggest a method to detect the Bolt Hole of the steel frame using the new detection that is combined template matching and the circular Hough transform. The template matching can be used to roughly estimate the location of the object under the various illumination. The circular Hough transform is used to discover more accurate location of the object than the template matching. Therefore, we compare the performance between each individual method and the mixed methods. We confirm that the proposed method is robust with respect to illumination.

  • Bolting robot assistance system using image processing
    ICCAS 2010, 2010
    Co-Authors: Yung Hak Mo, Yungeun Choe, Jung-min Park
    Abstract:

    The Bolting robot assistance system prevents operator to face dangerous situations. Bolting robot assistance system consists of Bolting robot control system and top-view supervisory system. In order to control a Bolting robot, Camshift algorithm and circular Hough transform are used. To estimate location of Bolt Hole, circular Hough transform is used. In order to track a Bolt Hole, Meanshift and Camshift are used. Camshift operates on color image represented by probability point and applies a non-parametric gradient density called Meanshift algorithm to re-center its operating window. By setting region to search a Bolt Hole, the algorithm will track the location of the Bolt Hole. In order to make top-view supervisory system, four cameras are installed at left, right, front and back of the robot. Each image from the camera is used to make the top-view image after correcting distortion. This paper proposes the image processing algorithm which is suitable for top-view supervisory system.

Jianyu Zhang - One of the best experts on this subject based on the ideXlab platform.

  • probabilistic Bolt load distribution analysis of composite single lap multi Bolt joints considering random Bolt Hole clearances and tightening torques
    Composite Structures, 2018
    Co-Authors: Meijuan Shan, Libin Zhao, Jianyu Zhang
    Abstract:

    Abstract This paper presents a stochastic Bolt load distribution analysis method of composite single-lap multi-Bolt joints by using an improved three-stage spring-based method and Monte Carlo simulation. In the proposed method, the random properties of tightening torque, Bolt-Hole clearance, lamina properties and geometric parameters were involved. The allowable manufacturing tolerance band of parameters and clearance fit were considered, and a combining distribution function consisting of binomial distribution and normal distribution function was adopted for modeling the random tightening torque relaxation. To validate the proposed method, a set of composite single-lap three-Bolt joints were designed and tested to achieve the stochastic Bolt load distribution of the joint. Good agreements between the numerical and experimental stochastic Bolt load distribution validated the proposed method. Furthermore, the probabilistic Bolt load distributions of the three-Bolt joints in four tightening torque conditions, including finger-tight, wrench torque, standard tightening torque and relaxation tightening torque, were investigated. It is found that tightening torque conditions and Bolt-Hole clearances have significant influences on the variation of the Bolt load distribution, while the effects of other random parameters on the variation of the Bolt load distribution are slight.

  • an interpretation of the load distributions in highly torqued single lap composite Bolted joints with Bolt Hole clearances
    Composites Part B-engineering, 2018
    Co-Authors: Xuheng Lu, Libin Zhao, Jianyu Zhang, Ning Hu, Jifeng Xu
    Abstract:

    Abstract A detailed interpretation of load distribution in composite single-lap Bolted joints is presented based on theoretical, experimental and numerical investigations. Modified instrumented Bolts (MIBs) were used to measure Bolt shear loads consisting of the Bolt bearing load and the friction force between the laminate and nut. The Bolt-load carrying mechanism in single-Bolt joints and the load transfer mechanism in multi-Bolt joints with various tightening torques and Bolt-Hole clearances were revealed based on theoretical and numerical analyses and validated against experimental results. The load transferred by each Bolt in a multi-Bolt joint was determined with greater fidelity, and the load distributions obtained using a three-dimensional finite element (FE) model and a spring-based method were compared. The load distributions obtained from the established 3D FE model were found to be identical to those obtained using the spring-based method; the Bolt-Hole clearances significantly impacted the load distributions, but the effects of the Bolt tightening torques on the load distributions could be ignored.

V P Lawlor - One of the best experts on this subject based on the ideXlab platform.

  • an experimental study of Bolt Hole clearance effects in double lap multi Bolt composite joints
    Composite Structures, 2005
    Co-Authors: V P Lawlor, M A Mccarthy, W F Stanley
    Abstract:

    Abstract An experimental study on the effects of variable Bolt–Hole clearance in double-lap, multi-Bolt joints is presented. Joints with different clearances in each Hole have been tested and the effects on load distribution, quasi-static strength, fatigue life and failure modes are reported. Strain gauges have been used for measuring load distribution and specialised jigs have been used for positioning the Bolts in the Holes and drilling the joints. The clearances examined ranged from neat-fit to clearances slightly larger than those allowed in the aircraft industry. Clearance has been found to have major effects on the load distribution; no effect on ultimate quasi-static strength but significant effect on failure initiation load; and quite significant effects on fatigue life.

  • An experimental study of Bolt–Hole clearance effects in double-lap, multi-Bolt composite joints
    Composite Structures, 2005
    Co-Authors: V P Lawlor, M A Mccarthy, W F Stanley
    Abstract:

    Abstract An experimental study on the effects of variable Bolt–Hole clearance in double-lap, multi-Bolt joints is presented. Joints with different clearances in each Hole have been tested and the effects on load distribution, quasi-static strength, fatigue life and failure modes are reported. Strain gauges have been used for measuring load distribution and specialised jigs have been used for positioning the Bolts in the Holes and drilling the joints. The clearances examined ranged from neat-fit to clearances slightly larger than those allowed in the aircraft industry. Clearance has been found to have major effects on the load distribution; no effect on ultimate quasi-static strength but significant effect on failure initiation load; and quite significant effects on fatigue life.

  • progressive damage analysis of multi Bolt composite joints with variable Bolt Hole clearances
    Composites Part B-engineering, 2005
    Co-Authors: C T Mccarthy, M A Mccarthy, V P Lawlor
    Abstract:

    Abstract A 3D progressive damage finite element model of multi-Bolt, double-lap composite joints is developed in the non-linear finite element code ABAQUS. The model is validated by comparing load–displacement characteristics and surface strains to experimental results. A study is then performed of the effects of variable Bolt–Hole clearance with results compared to experiments in which Bolt loads were measured in joints loaded to ultimate failure. It is shown that clearance can cause major changes in the load distribution and damage mechanisms in the joint. It can also lead to a significant reduction in the load at which initial failure (due to bearing at one of the Holes) occurs, making it an important variable to consider in the limit load design of aircraft. Unlike previous methods, the method presented here is capable of correctly accounting for bearing and bypass stresses, in the presence of damaged material properties, as well as the load re-distribution that occurs after bearing failure at one or more Holes.

  • Progressive damage analysis of multi-Bolt composite joints with variable Bolt–Hole clearances
    Composites Part B-engineering, 2005
    Co-Authors: Conor T. Mccarthy, M A Mccarthy, V P Lawlor
    Abstract:

    Abstract A 3D progressive damage finite element model of multi-Bolt, double-lap composite joints is developed in the non-linear finite element code ABAQUS. The model is validated by comparing load–displacement characteristics and surface strains to experimental results. A study is then performed of the effects of variable Bolt–Hole clearance with results compared to experiments in which Bolt loads were measured in joints loaded to ultimate failure. It is shown that clearance can cause major changes in the load distribution and damage mechanisms in the joint. It can also lead to a significant reduction in the load at which initial failure (due to bearing at one of the Holes) occurs, making it an important variable to consider in the limit load design of aircraft. Unlike previous methods, the method presented here is capable of correctly accounting for bearing and bypass stresses, in the presence of damaged material properties, as well as the load re-distribution that occurs after bearing failure at one or more Holes.

  • an experimental study of Bolt Hole clearance effects in single lap multiBolt composite joints
    Journal of Composite Materials, 2005
    Co-Authors: M A Mccarthy, V P Lawlor, W F Stanley
    Abstract:

    An experimental study on the effects of variable Bolt-Hole clearance in single-lap, multiBolt composite joints is presented. To the authors’ knowledge, this is the first time that clearance effects...