The Experts below are selected from a list of 47526 Experts worldwide ranked by ideXlab platform
Hui-shen Shen - One of the best experts on this subject based on the ideXlab platform.
-
postbuckling of 3d braided composite cylindrical shells under combined external pressure and axial compression in thermal environments
International Journal of Mechanical Sciences, 2008Co-Authors: Zhimin Li, Hui-shen ShenAbstract:Abstract A postbuckling analysis is presented for a three-dimensional (3D) braided composite cylindrical shell of finite length subjected to combined loading of external pressure and axial compression in thermal environments. Based on a micro–macro-mechanical model, a 3D braided composite may be a cell system and the geometry of each cell is highly dependent on its position in the cross-section of the cylindrical shell. The material properties of epoxy are expressed as a linear function of temperature. The governing equations are based on a higher order shear deformation shell theory with a von Karman–Donnell-type kinematic nonlinearity and includes thermal effects. A singular perturbation technique is employed to determine interactive buckling loads and postbuckling equilibrium paths. The numerical illustrations concern the postbuckling behavior of perfect and imperfect, braided composite cylindrical shells with different values of shell Geometric Parameter and of fiber volume fraction under combined loading conditions. The results show that the shell has lower buckling loads and postbuckling paths when the temperature-dependent properties are taken into account. The effects of temperature rise, fiber volume fraction, shell Geometric Parameter, load-proportional Parameter, as well as initial Geometric imperfections are studied.
Miguel Angel Sotelo - One of the best experts on this subject based on the ideXlab platform.
-
compensation of Geometric Parameter errors for terrestrial laser scanner by integrating intensity correction
IEEE Transactions on Geoscience and Remote Sensing, 2020Co-Authors: Wanli Liu, Shuaishuai Sun, Miguel Angel SoteloAbstract:The accuracy of Geometric Parameters (mainly referred to the incidence angle and measuring distance) in a terrestrial laser scanner (TLS) is not only influenced by the TLS intrinsic systematic instrumental error but also the extrinsic received intensity data. However, the current error compensation methods for Geometric Parameters mainly focus on the calibration of TLS intrinsic systematic instrumental error and rarely consider the extrinsic intensity data correction. For this reason, this article presents a new method integrating the TLS intrinsic systematic instrumental error calibration and extrinsic intensity data correction to compensate the TLS Geometric Parameter error. The error compensation procedure is implemented as follows. First, the error compensation mathematical model integrated with TLS intrinsic systematic instrumental error calibration Parameters and extrinsic intensity data correction coefficient is established. Second, the hybrid harmonic analysis (HA) and the adaptive wavelet neural network (AWNN) algorithm are proposed to calculate the TLS incidence angle error compensation values. Subsequently, the cubic spline interpolation (CSI) is applied to compute the measuring distance error compensate values. Finally, the TLS (model FARO Focus S150) and the hemispherical angle calibration instrument were used to evaluate the proposed compensation method. The experimental results demonstrate that the Geometric Parameters are significantly influenced by the intensity data received from TLS, and the proposed method can effectively improve the overall accuracy of the TLS incidence angle and measuring distance.
Zhimin Li - One of the best experts on this subject based on the ideXlab platform.
-
postbuckling of 3d braided composite cylindrical shells under combined external pressure and axial compression in thermal environments
International Journal of Mechanical Sciences, 2008Co-Authors: Zhimin Li, Hui-shen ShenAbstract:Abstract A postbuckling analysis is presented for a three-dimensional (3D) braided composite cylindrical shell of finite length subjected to combined loading of external pressure and axial compression in thermal environments. Based on a micro–macro-mechanical model, a 3D braided composite may be a cell system and the geometry of each cell is highly dependent on its position in the cross-section of the cylindrical shell. The material properties of epoxy are expressed as a linear function of temperature. The governing equations are based on a higher order shear deformation shell theory with a von Karman–Donnell-type kinematic nonlinearity and includes thermal effects. A singular perturbation technique is employed to determine interactive buckling loads and postbuckling equilibrium paths. The numerical illustrations concern the postbuckling behavior of perfect and imperfect, braided composite cylindrical shells with different values of shell Geometric Parameter and of fiber volume fraction under combined loading conditions. The results show that the shell has lower buckling loads and postbuckling paths when the temperature-dependent properties are taken into account. The effects of temperature rise, fiber volume fraction, shell Geometric Parameter, load-proportional Parameter, as well as initial Geometric imperfections are studied.
Wanli Liu - One of the best experts on this subject based on the ideXlab platform.
-
compensation of Geometric Parameter errors for terrestrial laser scanner by integrating intensity correction
IEEE Transactions on Geoscience and Remote Sensing, 2020Co-Authors: Wanli Liu, Shuaishuai Sun, Miguel Angel SoteloAbstract:The accuracy of Geometric Parameters (mainly referred to the incidence angle and measuring distance) in a terrestrial laser scanner (TLS) is not only influenced by the TLS intrinsic systematic instrumental error but also the extrinsic received intensity data. However, the current error compensation methods for Geometric Parameters mainly focus on the calibration of TLS intrinsic systematic instrumental error and rarely consider the extrinsic intensity data correction. For this reason, this article presents a new method integrating the TLS intrinsic systematic instrumental error calibration and extrinsic intensity data correction to compensate the TLS Geometric Parameter error. The error compensation procedure is implemented as follows. First, the error compensation mathematical model integrated with TLS intrinsic systematic instrumental error calibration Parameters and extrinsic intensity data correction coefficient is established. Second, the hybrid harmonic analysis (HA) and the adaptive wavelet neural network (AWNN) algorithm are proposed to calculate the TLS incidence angle error compensation values. Subsequently, the cubic spline interpolation (CSI) is applied to compute the measuring distance error compensate values. Finally, the TLS (model FARO Focus S150) and the hemispherical angle calibration instrument were used to evaluate the proposed compensation method. The experimental results demonstrate that the Geometric Parameters are significantly influenced by the intensity data received from TLS, and the proposed method can effectively improve the overall accuracy of the TLS incidence angle and measuring distance.
Bin Yan - One of the best experts on this subject based on the ideXlab platform.
-
a Parameter division based method for the Geometrical calibration of x ray industrial cone beam ct
IEEE Access, 2018Co-Authors: Kai Xiao, Yu Han, Bin YanAbstract:For X-ray cone-beam computed tomography (CBCT), non-calibrated system geometry causes indistinct and blurring artifacts in reconstructed images, which impacts on the image quality badly. This paper presents a practical industrial CBCT Geometric calibration method, which aims to determine the Geometric Parameter without extra phantom and benefit to efficiency for calibration. In our method, the Geometric Parameter is divided into system Parameter and imaging Parameter to be calibrated, respectively. First, the system Parameter was determined precisely at the first beginning via average for multiple measurements. Next, the imaging Parameter was determined via a designed algorithm in this paper based on the invariance of rotation axis. Furthermore, the proposed method only utilizes the projection data without reconstruction iteration to calibrate Geometric Parameter, which benefits to efficiency and practical industrial application. 3-D simulation data have been through test with and without noise, and the results show robust and accuracy on the proposed algorithm. In addition, it is also validated with various real data include printed circuit board and industrial components acquired at actual industrial CBCT. The results of reconstructed images demonstrate that the proposed method can achieve comparable image quality in the reconstruction as some phantom-based methods. Furthermore, the advantages and obstacle of the proposed method are analyzed and discussed in this paper.
