Gene Hou - Academia.edu (original) (raw)
Papers by Gene Hou
15th AIAA Computational Fluid Dynamics Conference, 2001
The design and integration of an impact-testing machine is particularly for the test of an object... more The design and integration of an impact-testing machine is particularly for the test of an object which is repeatedly dropped down from a specified height. Four linear actuators with two on each of the two magnetic rails are used to lift up an object weighing up to70 lbs. Each actuator is powered and controlled by an industrial amplifier. A Programmable Logical Controller (PLC) is applied to activate these four actuators simultaneously and repeatedly. Accelerometers using an National Instruments (NI) data acquisition system are used to measure the impact force during the tests. Students gain design and implementation experiences from the developing of the system.
This research follows the Mikropoulos and Natsis [1] notion of virtual reality (VR), who define i... more This research follows the Mikropoulos and Natsis [1] notion of virtual reality (VR), who define it as "a mosaic of technologies that support the creation of synthetic, highly interactive three-dimensional spatial environments that represent real or non-real situations." The dominant technology in VR is visual representation, namely virtual environment (VE). VE and VR are quite often interchangeable in the literature. VE along with technologies such as immersion, multisensory interaction and haptic devices has enabled VR to offer a first-order experience in emulating the natural environment and visualizing abstract ideas. As a result, VR has been proven to be effective in increasing knowledge construction and, thus, enhancing the learning outcome.
2017 ASEE Annual Conference & Exposition Proceedings
(ODU). He received his PhD in Mechanical Engineering from University of Iowa in 1983 and joined O... more (ODU). He received his PhD in Mechanical Engineering from University of Iowa in 1983 and joined Old Dominion University since then. His expertise is in computational mechanics, multidisciplinary design optimization and system integration and risk management. He is the co-director of the Marine Dynamics Laboratory. During his tenure, he has the privilege of developing 3 new undergraduate and 6 new graduate courses in the areas related to computational methods and design.
2017 ASEE Annual Conference & Exposition Proceedings
(ODU). He received his PhD in Mechanical Engineering from University of Iowa in 1983 and joined O... more (ODU). He received his PhD in Mechanical Engineering from University of Iowa in 1983 and joined Old Dominion University since then. His expertise is in computational mechanics, multidisciplinary design optimization and system integration and risk management. He is the co-director of the Marine Dynamics Laboratory. During his tenure, he has the privilege of developing 3 new undergraduate and 6 new graduate courses in the areas related to computational methods and design.
The focus of the paper is on the derivation of sensitivity equations for transient heat transfer ... more The focus of the paper is on the derivation of sensitivity equations for transient heat transfer problems modeled by different discretization processes. Two examples will be used in this study to facilitate the discussion. The first example is a coupled, transient heat transfer problem that simulates the press molding process in fabrication of composite laminates. These state equations are discretized into standard h-version finite elements and solved by a multiple step, predictor-corrector scheme. The sensitivity analysis results based upon the direct and adjoint variable approaches will be presented. The second example is a nonlinear transient heat transfer problem solved by a p-version time-discontinuous Galerkin's Method. The resulting matrix equation of the state equation is simply in the form of b x = A , representing a single step, time marching scheme. A direct differentiation approach will be used to compute the thermal sensitivities of a sample 2D problem.
Sports Engineering, 2015
The human foot is subjected to ground reaction forces during running. These forces have been stud... more The human foot is subjected to ground reaction forces during running. These forces have been studied for decades to reduce the related injuries and increase comfort. A four-degree-of-freedom system has been used in the literature to simulate the human body motion during the touchdown. However, there are still inconsistencies between the simulation results and experimental measurements. In this study, an optimization technique is proposed to obtain the required parameters to estimate the vertical ground reaction force using the measurements from actual runners. The touchdown velocities of the rigid and wobbling body masses were also treated as optimization variables. It was shown that the proposed parameters can be adjusted to represent a particular shoe type. Specifically, vertical ground reaction force parameters and touchdown velocities were obtained for shoes with various insole properties and cushioning technologies. The results of this study suggest that the human locomotion system reacts to the shoe properties by regulating the velocities of the body wobbling and rigid masses. The magnitude and the load rate obtained using the proposed parameters are consistent with the experimental data. It is shown that the viscoelastic properties of the shoe will significantly affect the load rate but not the load magnitude.
Aircraft Design and Operations Meeting, 1991
ABSTRACT
50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2009
ABSTRACT
5th Symposium on Multidisciplinary Analysis and Optimization, 1994
Journal of Structures, 2014
A systematic approach is presented in this paper to derive the analytical deflection function of ... more A systematic approach is presented in this paper to derive the analytical deflection function of a stepped beam using singularity functions. The discontinuities considered in this development are associated with the jumps in the flexural rigidity and the applied loads. This approach is applied to static and vibration analyses of stepped beams. The same approach is later extended to perform sensitivity analysis of stepped beams. This is done by directly differentiating the analytical deflection function with respect to any beam-related design variable. The particular design variable considered here is the location of discontinuity in flexural rigidity. Example problems are presented in this paper to demonstrate and verify the derivation process.
34th Structures, Structural Dynamics and Materials Conference, 1993
ABSTRACT
34th Structures, Structural Dynamics and Materials Conference, 1993
ABSTRACT
Astrodynamics Conference, 1992
ABSTRACT
34th Structures, Structural Dynamics and Materials Conference, 1993
ABSTRACT
14th Computational Fluid Dynamics Conference, 1999
The formulation and implementation of an optimization method called Simultaneous Aerodynamic Anal... more The formulation and implementation of an optimization method called Simultaneous Aerodynamic Analysis and Design Optimization (SAADO) are extended from single discipline analysis (aerodynamics only) to multidisciplinary analysis-in this case, static aero-structural analysisand applied to a simple 3-D wing problem. The method aims to reduce the computational expense incurred in performing shape optimization using state-of-the-art Computational Fluid Dynamics (CFD) flow analysis, Finite Element Method (FEM) structural analysis and sensitivity analysis tools. Results for this small problem show that the method reaches the same local optimum as conventional optimization. However, unlike its application to the rigid wing (single discipline analysis), the method, as implemented here, may not show significant reduction in the computational cost. Similar reductions were seen in the two-design-variable (DV) problem results but not in the 8-DV results given here.
Computational Mechanics ’95, 1995
In many engineering applications, selection of subcomponents for assembly into a useful structure... more In many engineering applications, selection of subcomponents for assembly into a useful structure is a more important design decision than modification of the detailed dimensions of individual subcomponent. Examples in the automobile industry include selection of strength members of the roof of a van to enhance buckling resistance or placement of engine support members in the chassis of a truck to reduce vibration. In these problems, the design variables are the subcomponents themselves, rather than the dimensions of the subcomponents.
32nd Structures, Structural Dynamics, and Materials Conference, 1991
A general procedure is developed for calculating aerodynamic sensitivity coefficients using the f... more A general procedure is developed for calculating aerodynamic sensitivity coefficients using the full equations of fluid flow, where the focus of the work is the treatment of arbitrary variations of geometric shape design varibles. Using an upwind cell-centered finite volume approximation to represent the governing equations, sensitivity derivatives are determined by direct differentiation of the resulting set of coupled nonlinear algebriac equations which model the fluid flow. The technique is implemented and succesfully tested in 2D for inviscid flow (i.e., the Euler equations) through a subsonic nozzle (M, = 0.85), and also a supersonic inlet (M, = 2.0). Specifically, the method is demonstrated by calculating the sensitivity of the aerodynamic loads (forces) on the interior walls of the nozzle / inlet to variations in the geometric parameters which define their shape. The sensitivity coefficients calculated using this approach compare very well with those calculated using the method of "brute force" (i.e., using finite differences to approximate the sensitivity derivatives), and are computationally less expensive to obtain.
SAE Technical Paper Series, 2005
15th AIAA Computational Fluid Dynamics Conference, 2001
The design and integration of an impact-testing machine is particularly for the test of an object... more The design and integration of an impact-testing machine is particularly for the test of an object which is repeatedly dropped down from a specified height. Four linear actuators with two on each of the two magnetic rails are used to lift up an object weighing up to70 lbs. Each actuator is powered and controlled by an industrial amplifier. A Programmable Logical Controller (PLC) is applied to activate these four actuators simultaneously and repeatedly. Accelerometers using an National Instruments (NI) data acquisition system are used to measure the impact force during the tests. Students gain design and implementation experiences from the developing of the system.
This research follows the Mikropoulos and Natsis [1] notion of virtual reality (VR), who define i... more This research follows the Mikropoulos and Natsis [1] notion of virtual reality (VR), who define it as "a mosaic of technologies that support the creation of synthetic, highly interactive three-dimensional spatial environments that represent real or non-real situations." The dominant technology in VR is visual representation, namely virtual environment (VE). VE and VR are quite often interchangeable in the literature. VE along with technologies such as immersion, multisensory interaction and haptic devices has enabled VR to offer a first-order experience in emulating the natural environment and visualizing abstract ideas. As a result, VR has been proven to be effective in increasing knowledge construction and, thus, enhancing the learning outcome.
2017 ASEE Annual Conference & Exposition Proceedings
(ODU). He received his PhD in Mechanical Engineering from University of Iowa in 1983 and joined O... more (ODU). He received his PhD in Mechanical Engineering from University of Iowa in 1983 and joined Old Dominion University since then. His expertise is in computational mechanics, multidisciplinary design optimization and system integration and risk management. He is the co-director of the Marine Dynamics Laboratory. During his tenure, he has the privilege of developing 3 new undergraduate and 6 new graduate courses in the areas related to computational methods and design.
2017 ASEE Annual Conference & Exposition Proceedings
(ODU). He received his PhD in Mechanical Engineering from University of Iowa in 1983 and joined O... more (ODU). He received his PhD in Mechanical Engineering from University of Iowa in 1983 and joined Old Dominion University since then. His expertise is in computational mechanics, multidisciplinary design optimization and system integration and risk management. He is the co-director of the Marine Dynamics Laboratory. During his tenure, he has the privilege of developing 3 new undergraduate and 6 new graduate courses in the areas related to computational methods and design.
The focus of the paper is on the derivation of sensitivity equations for transient heat transfer ... more The focus of the paper is on the derivation of sensitivity equations for transient heat transfer problems modeled by different discretization processes. Two examples will be used in this study to facilitate the discussion. The first example is a coupled, transient heat transfer problem that simulates the press molding process in fabrication of composite laminates. These state equations are discretized into standard h-version finite elements and solved by a multiple step, predictor-corrector scheme. The sensitivity analysis results based upon the direct and adjoint variable approaches will be presented. The second example is a nonlinear transient heat transfer problem solved by a p-version time-discontinuous Galerkin's Method. The resulting matrix equation of the state equation is simply in the form of b x = A , representing a single step, time marching scheme. A direct differentiation approach will be used to compute the thermal sensitivities of a sample 2D problem.
Sports Engineering, 2015
The human foot is subjected to ground reaction forces during running. These forces have been stud... more The human foot is subjected to ground reaction forces during running. These forces have been studied for decades to reduce the related injuries and increase comfort. A four-degree-of-freedom system has been used in the literature to simulate the human body motion during the touchdown. However, there are still inconsistencies between the simulation results and experimental measurements. In this study, an optimization technique is proposed to obtain the required parameters to estimate the vertical ground reaction force using the measurements from actual runners. The touchdown velocities of the rigid and wobbling body masses were also treated as optimization variables. It was shown that the proposed parameters can be adjusted to represent a particular shoe type. Specifically, vertical ground reaction force parameters and touchdown velocities were obtained for shoes with various insole properties and cushioning technologies. The results of this study suggest that the human locomotion system reacts to the shoe properties by regulating the velocities of the body wobbling and rigid masses. The magnitude and the load rate obtained using the proposed parameters are consistent with the experimental data. It is shown that the viscoelastic properties of the shoe will significantly affect the load rate but not the load magnitude.
Aircraft Design and Operations Meeting, 1991
ABSTRACT
50th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2009
ABSTRACT
5th Symposium on Multidisciplinary Analysis and Optimization, 1994
Journal of Structures, 2014
A systematic approach is presented in this paper to derive the analytical deflection function of ... more A systematic approach is presented in this paper to derive the analytical deflection function of a stepped beam using singularity functions. The discontinuities considered in this development are associated with the jumps in the flexural rigidity and the applied loads. This approach is applied to static and vibration analyses of stepped beams. The same approach is later extended to perform sensitivity analysis of stepped beams. This is done by directly differentiating the analytical deflection function with respect to any beam-related design variable. The particular design variable considered here is the location of discontinuity in flexural rigidity. Example problems are presented in this paper to demonstrate and verify the derivation process.
34th Structures, Structural Dynamics and Materials Conference, 1993
ABSTRACT
34th Structures, Structural Dynamics and Materials Conference, 1993
ABSTRACT
Astrodynamics Conference, 1992
ABSTRACT
34th Structures, Structural Dynamics and Materials Conference, 1993
ABSTRACT
14th Computational Fluid Dynamics Conference, 1999
The formulation and implementation of an optimization method called Simultaneous Aerodynamic Anal... more The formulation and implementation of an optimization method called Simultaneous Aerodynamic Analysis and Design Optimization (SAADO) are extended from single discipline analysis (aerodynamics only) to multidisciplinary analysis-in this case, static aero-structural analysisand applied to a simple 3-D wing problem. The method aims to reduce the computational expense incurred in performing shape optimization using state-of-the-art Computational Fluid Dynamics (CFD) flow analysis, Finite Element Method (FEM) structural analysis and sensitivity analysis tools. Results for this small problem show that the method reaches the same local optimum as conventional optimization. However, unlike its application to the rigid wing (single discipline analysis), the method, as implemented here, may not show significant reduction in the computational cost. Similar reductions were seen in the two-design-variable (DV) problem results but not in the 8-DV results given here.
Computational Mechanics ’95, 1995
In many engineering applications, selection of subcomponents for assembly into a useful structure... more In many engineering applications, selection of subcomponents for assembly into a useful structure is a more important design decision than modification of the detailed dimensions of individual subcomponent. Examples in the automobile industry include selection of strength members of the roof of a van to enhance buckling resistance or placement of engine support members in the chassis of a truck to reduce vibration. In these problems, the design variables are the subcomponents themselves, rather than the dimensions of the subcomponents.
32nd Structures, Structural Dynamics, and Materials Conference, 1991
A general procedure is developed for calculating aerodynamic sensitivity coefficients using the f... more A general procedure is developed for calculating aerodynamic sensitivity coefficients using the full equations of fluid flow, where the focus of the work is the treatment of arbitrary variations of geometric shape design varibles. Using an upwind cell-centered finite volume approximation to represent the governing equations, sensitivity derivatives are determined by direct differentiation of the resulting set of coupled nonlinear algebriac equations which model the fluid flow. The technique is implemented and succesfully tested in 2D for inviscid flow (i.e., the Euler equations) through a subsonic nozzle (M, = 0.85), and also a supersonic inlet (M, = 2.0). Specifically, the method is demonstrated by calculating the sensitivity of the aerodynamic loads (forces) on the interior walls of the nozzle / inlet to variations in the geometric parameters which define their shape. The sensitivity coefficients calculated using this approach compare very well with those calculated using the method of "brute force" (i.e., using finite differences to approximate the sensitivity derivatives), and are computationally less expensive to obtain.
SAE Technical Paper Series, 2005