Yu-Ching Yang

Kun Shan University, Kao-hsiung, Taiwan, Taiwan

Are you Yu-Ching Yang?

Claim your profile

Publications (73)146.81 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, an inverse algorithm based on the conjugate gradient method and the discrepancy principle is applied to solve the inverse hyperbolic heat conduction problem with the dual-phase-lag heat transfer model in estimating the unknown boundary pulse heat flux in an infinitely long solid cylinder from the temperature measurements taken within the medium. An efficient numerical scheme involving the hybrid application of the Laplace transform and control volume methods in conjunction with hyperbolic shape functions is used to solve the hyperbolic direct problem. The inverse solutions will be justified based on the numerical experiments in which two different heat flux distributions are to be determined. The temperature data obtained from the direct problem are used to simulate the temperature measurements. The influence of measurement errors upon the precision of the estimated results is also investigated. Results show that an excellent estimation on the time-dependent pulse heat flux can be obtained for the test cases considered in this study.
    International Communications in Heat and Mass Transfer 11/2014; 60. DOI:10.1016/j.icheatmasstransfer.2014.11.002 · 2.12 Impact Factor
  • Haw-Long Lee, Yu-Ching Yang, Win-Jin Chang
    Microscopy and Microanalysis 08/2014; 20(S3):1940-1941. DOI:10.1017/S143192761401143X · 1.76 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, an inverse algorithm based on the conjugate gradient method and the discrepancy principle is applied to solve the inverse hyperbolic heat conduction problem in estimating the unknown time-dependent surface heat flux in a skin tissue, which is stratified into epidermis, dermis, and subcutaneous layers, from the temperature measurements taken within the medium. Subsequently, the temperature distributions in the tissue can be calculated as well. The concept of finite heat propagation velocity is applied to the modeling of the bioheat transfer problem. The inverse solutions will be justified based on the numerical experiments in which two different heat flux distributions are to be determined. The temperature data obtained from the direct problem are used to simulate the temperature measurements. The influence of measurement errors on the precision of the estimated results is also investigated. Results show that an excellent estimation on the time-dependent surface heat flux can be obtained for the test cases considered in this study.
    Computer Methods in Biomechanics and Biomedical Engineering 06/2014; 18(14):1-10. DOI:10.1080/10255842.2014.925108 · 1.79 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, an inverse algorithm based on the conjugate gradient method and the discrepancy principle is applied to simultaneously estimate the unknown boundary heat flux and convective heat transfer coefficient in a curved plate cooled by an impinging slot jet from the knowledge of temperature measurements taken within the plate. Subsequently, the distributions of temperature in the plate can be determined. It is assumed that no prior information is available on the functional forms of the heat flux and convective heat transfer coefficient; hence the procedure is classified as the function estimation in inverse calculation. The temperature data obtained from the direct problem are used to simulate the temperature measurements, and the effect of the errors and locations in these measurements upon the precision of the estimated results is also considered. Results show that an excellent estimation on the heat flux and convective heat transfer coefficient and temperature distributions can be obtained for the two test cases considered in this study.
    Numerical Heat Transfer Applications 05/2014; 66(3). DOI:10.1080/10407782.2013.873264 · 1.85 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, an inverse algorithm based on the conjugate gradient method and the discrepancy principle is applied to solve the inverse hyperbolic heat conduction problem with a dual-phase-lag model to estimate the unknown space- and time-dependent energy absorption rate in a thin metal film exposed to short-pulse laser heating from the temperature measurements taken within the medium. Subsequently, the temperature distributions in the metal film can be determined as well. The inverse solutions are justified based on the numerical experiments in which two different energy absorption rates are estimated. The temperature data obtained from the direct problem are used to simulate the temperature measurements. The influence of measurement errors upon the precision of the estimated results is also investigated. Results show that an excellent estimation on the laser energy absorption rate can be obtained for the test cases considered in this study.
    Applied Thermal Engineering 04/2014; 65(s 1–2):352–360. DOI:10.1016/j.applthermaleng.2014.01.024 · 2.62 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, an inverse algorithm based on the conjugate gradient method and the discrepancy principle is applied to solve the inverse hyperbolic heat conduction problem in estimating the unknown space- and time-dependent base heat flux of a cylindrical pin fin from the knowledge of temperature measurements taken within the medium. The inverse solutions have been justified based on the numerical experiments in which three specific cases to determine the unknown base heat flux are examined. The temperature data obtained from the direct problem are used to simulate the temperature measurements. The influence of measurement errors upon the precision of the estimated results is also investigated. Results show that an excellent estimation on the space- and time-dependent base heat flux can be obtained for the test cases considered in this study.
    International Communications in Heat and Mass Transfer 03/2014; 52. DOI:10.1016/j.icheatmasstransfer.2014.01.020 · 2.12 Impact Factor
  • Win-Jin Chang, Haw-Long Lee, Yu-Ching Yang
    [Show abstract] [Hide abstract]
    ABSTRACT: This article theoretically analyzes the cutting depth and material removal rate of an atomic force microscope (AFM) cantilever during nanomachining. An analytical expression for the vibration frequency and displacement of the cantilever has been obtained by using the modified couple stress theory. The theory includes one additional material length scale parameter revealing the micro-scale effect. According to the analysis, the results show that the effect of size-dependent on the vibration behavior of the AFM cantilever is obvious. The maximum displacement of nanomachining with the AFM cantilever represents the cutting depth. The area under the displacement-time curve is related to the material removal rate. When the excitation frequency is closer to the nature frequency of the cantilever, a larger material removal rate is obtained.
    Journal of Physics Conference Series 02/2014; 490(1). DOI:10.1088/1742-6596/490/1/012161
  • Win-Jin Chang, Yu-Ching Yang, Haw-Long Lee
    [Show abstract] [Hide abstract]
    ABSTRACT: A modified couple stress theory is used to analyse the dynamic displacement of an atomic force microscope (AFM) cantilever during nanomachining. According to the analysis, the results show that the effect of size-dependence on the vibration behaviour of the AFM cantilever is obvious. The displacement obtained based on the modified couple stress theory is lower than that based on the classical beam theory. The maximum displacement of nanomachining with the AFM cantilever represents the cutting depth. When the excitation frequency is closer to the natural frequency of the cantilever, a larger material removal rate is obtained.
    Micro & Nano Letters 11/2013; 8(11):832-835. DOI:10.1049/mnl.2013.0493 · 0.80 Impact Factor
  • Wen-Lih Chen, Huann-Ming Chou, Yu-Ching Yang
    [Show abstract] [Hide abstract]
    ABSTRACT: In this study, an inverse algorithm based on the conjugate gradient method and the discrepancy principle is applied to estimate the unknown space-dependent thermal conductivity of a functionally graded hollow cylinder. Two different boundary condition types are discussed. The results show that boundary condition type is very crucial to the success of the inverse method. For the case studied here, the inverse method works in conjunction with heat flux specified at the inner wall and convective heat transfer condition at the outer wall but not with constant temperatures specified at both inner and outer walls. The effect of measurement error and sensor number on the estimation accuracy is also investigated. The method can be developed into an accurate, simple, and inexpensive technique for the quality control during the manufacture of functionally graded materials.
    Composites Part B Engineering 07/2013; 50:112–119. DOI:10.1016/j.compositesb.2013.02.010 · 2.60 Impact Factor
  • Yu-Ching Yang, Win-Jin Chang, Haw-Long Lee
    [Show abstract] [Hide abstract]
    ABSTRACT: In the paper, the coupled equation of motion for the dynamic displacement of a C-60 fullerene moving in a (10,10) single-walled carbon nanotube (SWCNT) is derived using nonlocal Timoshenko beam theory, including the effects of rotary inertia and shear deformation. The effects of confined stiffness between the C-60 fullerene and nanotube, foundation stiffness, and nonlocal parameter on the dynamic behavior are analyzed using the Runge-Kutta Method. The numerical solution is in agreement with the analytical result for the special case. The numerical results show that increasing the confined stiffness and foundation stiffness decrease the dynamic displacement of SWCNT. However, the dynamic displacement increases with increasing the nonlocal parameter. In addition, result using the Euler beam theory and the Timoshenko beam theory are compared. It can be found that ignoring the effects of rotary inertia and shear deformation leads to an underestimation of the displacement.
    Journal of Computational and Theoretical Nanoscience 06/2013; 10(6):1472-1476. DOI:10.1166/jctn.2013.2875 · 1.03 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, an inverse algorithm based on the conjugate gradient method and the discrepancy principle is applied to solve the inverse hyperbolic heat conduction problem in estimating the unknown time-dependent inner-wall heat flux of a hollow cylinder from the knowledge of temperature measurements taken within the medium. The inverse solutions have been justified through the numerical experiments in two specific cases to determine the unknown heat flux. Temperature data obtained from the direct problem are used to simulate the temperature measurements. The influence of measurement errors upon the precision of the estimated results is also investigated. Results show that excellent estimation on the time-dependent heat flux can be obtained for the test cases considered in this study. Once heat flux variation is accurately estimated, the evolution of temperature, displacement, and stress distributions can be calculated in great precision.
    International Journal of Heat and Mass Transfer 05/2013; 60:125-133. DOI:10.1016/j.ijheatmasstransfer.2012.12.052 · 2.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, the dual phase lag (DPL) heat transfer model is applied to investigate the transient heat transfer in a thin metal film exposed to short-pulse laser heating. An efficient numerical scheme involving the hybrid application of the Laplace transform and control volume methods in conjunction with hyperbolic shape functions is used to solve the hyperbolic heat conduction equation in the linearized form of DPL model. The transformed nodal temperatures are inverted to the physical quantities by using numerical inversion of the Laplace transform. Comparison between the numerical results and the analytic solution for a short-pulse laser heating with the Gaussian temporal profile evidences the accuracy of the present numerical results. Effect of different phase lags values of the heat flux and the temperature gradient on the behavior of heat transfer is also investigated. The results show that the phase lag of the heat flux tends to induce thermal waves with sharp wave-fronts separating heated and unheated zones in the metal film, while the phase lag of the temperature gradient destroys the waveforms and increases the thermally disturbed zone.
    Applied Thermal Engineering 04/2013; 52(2):275–283. DOI:10.1016/j.applthermaleng.2012.12.019 · 2.62 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, an inverse algorithm based on the conjugate gradient method and the discrepancy principle is applied to solve the inverse hyperbolic heat conduction problem in estimating the unknown time-dependent surface heat flux in a living skin tissue from the temperature measurements taken within the tissue. The inverse solutions will be justified based on the numerical experiments in which three different heat flux distributions are to be determined. The temperature data obtained from the direct problem are used to simulate the temperature measurements. The influence of measurement errors upon the precision of the estimated results is also investigated. Results show that an excellent estimation on the time-dependent surface heat flux can be obtained for the test cases considered in this study.
    Applied Mathematical Modelling 03/2013; 37(5):2630–2643. DOI:10.1016/j.apm.2012.06.025 · 2.16 Impact Factor
  • Haw-Long Lee, Yu-Ching Yang, Win-Jin Chang
    [Show abstract] [Hide abstract]
    ABSTRACT: The potential of using graphene as a nanomechanical resonator is explored. A graphene-resonator sensor is assumed to be a simply supported rectangular plate. The frequency equation of the sensor with an attached mass is derived analytically using nonlocal elasticity theory. The results indicate that increasing the nonlocal parameter markedly increases the frequency shift of the sensor, and the frequency shift becomes larger as the aspect ratio approaches 1. Therefore, in order to obtain the highest sensitivity, a square geometrical sensor should be used. The mass sensitivity can reach up to 10-27 g/Hz.
    Japanese Journal of Applied Physics 02/2013; 52(2):5101-. DOI:10.7567/JJAP.52.025101 · 1.06 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, an inverse algorithm based on the conjugate gradient method and the discrepancy principle is applied to estimate the unknown time-dependent base heat flux of a functionally graded fin from the knowledge of temperature measurements taken within the fin. Subsequently, the distributions of temperature and thermal stresses in the fin can be determined as well. It is assumed that no prior information is available on the functional form of the unknown base heat flux; hence the procedure is classified as the function estimation in inverse calculation. The temperature data obtained from the direct problem are used to simulate the temperature measurements. The influence of measurement errors and measurement location upon the precision of the estimated results is also investigated. Results show that an excellent estimation on the time-dependent base heat flux, temperature distributions, and thermal stresses can be obtained for the test case considered in this study.
    Journal of Thermal Stresses 09/2012; 35(9):733-748. DOI:10.1080/01495739.2012.689229 · 1.17 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper numerically investigates the hyperbolic thermoelastic problem of an annular fin. The ambient convection heat transfer coefficient of the fin is assumed to be spatially varying. The major difficulty in dealing with such problems is the suppression of numerical oscillations in the vicinity of a jump discontinuity. An efficient numerical scheme involving hybrid application of Laplace transform and control volume method in conjunction with hyperbolic shape functions is used to solve the linear hyperbolic heat conduction equation. The transformed nodal temperatures are inverted to the physical quantities by using numerical inversion of the Laplace transform. Then the stress distributions in the annular fin are calculated subsequently. The results in the illustrated examples show that the application of hyperbolic shape functions can successfully suppress the numerical oscillations in the vicinity of jump discontinuities.
    International Journal of Thermophysics 06/2012; 33(6). DOI:10.1007/s10765-012-1220-2 · 0.62 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, an inverse algorithm based on the conjugate gradient method and the discrepancy principle is applied to estimate the unknown time-dependent base heat flux of a functionally graded fin from the knowledge of temperature measurements taken within the fin. Subsequently, the distributions of temperature in the fin can be determined as well. It is assumed that no prior information is available on the functional form of the unknown base heat flux; hence the procedure is classified as the function estimation in inverse calculation. The temperature data obtained from the direct problem are used to simulate the temperature measurements. The influence of measurement errors and measurement location upon the precision of the estimated results is also investigated. Results show that an excellent estimation on the time-dependent base heat flux and temperature distributions can be obtained for the test case considered in this study.
    Energy Conversion and Management 05/2012; 57:1–7. DOI:10.1016/j.enconman.2011.12.002 · 3.59 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, an inverse algorithm based on the conjugate gradient method and the discrepancy principle is applied to simultaneously estimate the unknown time-dependent inner and outer boundary heat fluxes in a functionally graded hollow circular cylinder from the knowledge of temperature measurements taken within the cylinder. Subsequently, the distributions of temperature and thermal stresses in the cylinder can be determined as well. It is assumed that no prior information is available on the functional forms of the unknown heat fluxes; hence the procedure is classified as the function estimation in inverse calculation. The temperature data obtained from the direct problem are used to simulate the temperature measurements, and the effect of the errors and locations in these measurements upon the precision of the estimated results is also considered. Results show that an excellent estimation on the time-dependent heat fluxes, temperature distributions, and thermal stresses can be obtained for the test case considered in this study.
    Composites Part B Engineering 03/2012; 43(2):786–792. DOI:10.1016/j.compositesb.2011.11.055 · 2.60 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This article investigates the transient microbending loss and refractive index changes in a tightly jacketed double-coated optical fiber subjected to thermal loading with stress-dependent interlayer thermal contact resistance. The effects of interlayer thermal resistance on the transient microbending loss and refractive index changes of the optical fiber are analyzed and discussed. Results show that the stress-dependent interlayer thermal contact resistance increases the lateral pressure induced by the transient thermal loading in the tightly jacketed double-coated optical fiber and, thus, the microbending loss. Similarly, the interlayer thermal contact resistance increases the thermal loading induced refractive index changes in the transient state of the loading.
    Optics Communications 02/2012; DOI:10.1016/j.optcom.2011.10.003 · 1.54 Impact Factor
  • Source
    Yu-Ching Yang, Wen-Lih Chen
    [Show abstract] [Hide abstract]
    ABSTRACT: In this study, an inverse algorithm based on the conjugate gradient method and the discrepancy principle is applied to estimate the unknown space- and time-dependent heat flux of the disc in a disc brake system from the knowledge of temperature measurements taken within the disc. In the direct problem, the specific heat and thermal conductivity are functions of temperature; hence this is a nonlinear inverse problem. The temperature data obtained from the direct problem are used to simulate the temperature measurements, and the effect of the errors in these measurements upon the precision of the estimated results is also considered. Results show that an excellent estimation on the space- and time-dependent heat flux can be obtained for the test cases considered in this study. The current methodology can be also applied to the prediction of heat flux in the pads, and then the heat partition coefficient between the disc and the pad in a brake system can be calculated.
    Applied Thermal Engineering 10/2011; 31(14):2439-2448. DOI:10.1016/j.applthermaleng.2011.04.008 · 2.62 Impact Factor