In this paper we report on our efforts in fall semester 2010 to introduce system engineering fund... more In this paper we report on our efforts in fall semester 2010 to introduce system engineering fundamentals to students from the traditional engineering disciplines through an existing senior-level multidisciplinary capstone course, Interdisciplinary Capstone Design Project (ICDP). The course is open to students from biomedical engineering, chemical engineering, computer engineering, electrical engineering, mechanical engineering, and industrial engineering. While all engineering students at The Pennsylvania State University complete a capstone design course, most students complete a discipline-specific capstone. An interdisciplinary design course that meets ABET criteria for the engineering majors listed above has been developed by Penn State to allow students to work on multidisciplinary, innovative design. This course, therefore, serves as an ideal test bed for the introduction of systems engineering into a senior capstone design course. Teams apply fundamental design and analysis ...
In order to increase vehicle fuel efficiency while improving safety and performance and maintaini... more In order to increase vehicle fuel efficiency while improving safety and performance and maintaining affordability, the global steel industry has initiated the use of advanced high strength steels that ultimately result in the design of stronger, lighter and more energy efficient vehicles. Tubular steel columns are extensively used in the automotive body structure due to their inherent capacity to absorb energy on impact. Hence, the objective of this research work is to study the crashworthiness performance of spot-welded columns made from advanced high strength steels. It is shown that numerical results of the developed robust finite element model give fairly good agreement with experimental data in terms of collapse profile, deformed column shape, final crush length, and impact peak force. Throughout the investigation, the finite element model permits the study of several structural and material variables that can be validated by a moderate set of destructive tests. Moreover, the c...
An experimental and numerical study was performed to evaluate the crashworthiness of several adva... more An experimental and numerical study was performed to evaluate the crashworthiness of several advanced high strength steels. The behavior of two Dual Phase (DP) steels and an HSLA steel are compared by examining the crush response of longeron column ...
ABSTRACT Criteria for predicting the workability limits for internal failure in dual-phase steel ... more ABSTRACT Criteria for predicting the workability limits for internal failure in dual-phase steel cold-headed parts are presented in this paper. This workability criterion is divided into two sub-criteria to predict the two internal defect types triggered by the adiabatic shear band (ASB) phenomena. These defects are internal voids and cracks (deformed ASB) and/or development of brittle martensite inside the band as a result of phase transformation due to the temperature rise inside the ASB (transformed ASB). The presence of one or both failure types may result in splitting of the fastener's heads.
ABSTRACT A high-speed optical measurement system, which is capable of measuring transient surface... more ABSTRACT A high-speed optical measurement system, which is capable of measuring transient surface shape, is used in the polymer membrane inflation experiments. The accurate measurement data, which is an array of points, with known Cartesian coordinates and with respect to a fixed coordinate system, provides a source for further bubble shape analysis. Inflation pressure is correlated with each bubble shape measurement. The measured results reveal the importance of the thermal warpage and temperature gradient in the bubble inflation tests. Potential errors in the material parameter calculation, which are caused by assuming uniform temperature and zero thermal warpage, are pointed out. Consequently, a finite element analysis has been carried out to simulate the membrane inflation with/without thermal warpage and the temperature gradient. The material parameters obtained considering the thermal warpage and temperature gradient yield improved agreement with the experimental data. Although in this paper the measurement data is mainly used for the determination of the material parameters in the bubble inflation tests, they are also a source of validating other computer-aided simulations as well as in the study of the thermal shrinkage of polymer products.
ABSTRACT An optical surface measurement system, which is capable of measuring transient surface s... more ABSTRACT An optical surface measurement system, which is capable of measuring transient surface shape, has been developed by using a high-speed digital camera. The system is based on the grating projection and Fourier transform technique. A calibration procedure is developed to allow the system to generate Cartesian coordinates directly, which are with respect to a fixed coordinate system in 3-D space. The measurement accuracy (±50 μm) is defined and verified as the maximum error between measured values and the known values of standard objects both flat and curved. The camera and a grating projector are mounted into a portable sensor head to allow in situ measurements. In addition, external force or pressure signals can be correlated with each measurement through a device called the multi-channel data link. The system is capable of digitizing a 3-D curved surface into an array of points with known xyz coordinates at a sampling rate from 30 to 1000 Hz. As an application, the system is used to measure the transient surface shape during a polymer membrane inflation test. The measurement results along with the pressure information provide an approach to determine the material parameters used in different material models.
This paper introduces a new methodology from which better material parameters may be identified. ... more This paper introduces a new methodology from which better material parameters may be identified. The method will account for both non-repeatability of test data (by means of signal-to-noise weighting factors) and potential discrepancies between material parameters in different deformation modes (by means of a multi-objective optimization process). Finally, to show the application of the method, test data for a 2×2 twill weave fabric from different modes (namely, uniaxial extension and bias-extension) are selected to identify the model parameters of an orthotropic material model. The procedure may be applied to other material models and applications.
Journal of Engineering Materials and Technology, 2004
Engineering test data occasionally violate assumptions underlying standard material model identif... more Engineering test data occasionally violate assumptions underlying standard material model identification. Consequently, one has to apply appropriate remedies with respect to each violation to enhance the reliability of identified material parameters. This paper generalizes the use ...
In this paper we report on our efforts in fall semester 2010 to introduce system engineering fund... more In this paper we report on our efforts in fall semester 2010 to introduce system engineering fundamentals to students from the traditional engineering disciplines through an existing senior-level multidisciplinary capstone course, Interdisciplinary Capstone Design Project (ICDP). The course is open to students from biomedical engineering, chemical engineering, computer engineering, electrical engineering, mechanical engineering, and industrial engineering. While all engineering students at The Pennsylvania State University complete a capstone design course, most students complete a discipline-specific capstone. An interdisciplinary design course that meets ABET criteria for the engineering majors listed above has been developed by Penn State to allow students to work on multidisciplinary, innovative design. This course, therefore, serves as an ideal test bed for the introduction of systems engineering into a senior capstone design course. Teams apply fundamental design and analysis ...
In order to increase vehicle fuel efficiency while improving safety and performance and maintaini... more In order to increase vehicle fuel efficiency while improving safety and performance and maintaining affordability, the global steel industry has initiated the use of advanced high strength steels that ultimately result in the design of stronger, lighter and more energy efficient vehicles. Tubular steel columns are extensively used in the automotive body structure due to their inherent capacity to absorb energy on impact. Hence, the objective of this research work is to study the crashworthiness performance of spot-welded columns made from advanced high strength steels. It is shown that numerical results of the developed robust finite element model give fairly good agreement with experimental data in terms of collapse profile, deformed column shape, final crush length, and impact peak force. Throughout the investigation, the finite element model permits the study of several structural and material variables that can be validated by a moderate set of destructive tests. Moreover, the c...
An experimental and numerical study was performed to evaluate the crashworthiness of several adva... more An experimental and numerical study was performed to evaluate the crashworthiness of several advanced high strength steels. The behavior of two Dual Phase (DP) steels and an HSLA steel are compared by examining the crush response of longeron column ...
ABSTRACT Criteria for predicting the workability limits for internal failure in dual-phase steel ... more ABSTRACT Criteria for predicting the workability limits for internal failure in dual-phase steel cold-headed parts are presented in this paper. This workability criterion is divided into two sub-criteria to predict the two internal defect types triggered by the adiabatic shear band (ASB) phenomena. These defects are internal voids and cracks (deformed ASB) and/or development of brittle martensite inside the band as a result of phase transformation due to the temperature rise inside the ASB (transformed ASB). The presence of one or both failure types may result in splitting of the fastener's heads.
ABSTRACT A high-speed optical measurement system, which is capable of measuring transient surface... more ABSTRACT A high-speed optical measurement system, which is capable of measuring transient surface shape, is used in the polymer membrane inflation experiments. The accurate measurement data, which is an array of points, with known Cartesian coordinates and with respect to a fixed coordinate system, provides a source for further bubble shape analysis. Inflation pressure is correlated with each bubble shape measurement. The measured results reveal the importance of the thermal warpage and temperature gradient in the bubble inflation tests. Potential errors in the material parameter calculation, which are caused by assuming uniform temperature and zero thermal warpage, are pointed out. Consequently, a finite element analysis has been carried out to simulate the membrane inflation with/without thermal warpage and the temperature gradient. The material parameters obtained considering the thermal warpage and temperature gradient yield improved agreement with the experimental data. Although in this paper the measurement data is mainly used for the determination of the material parameters in the bubble inflation tests, they are also a source of validating other computer-aided simulations as well as in the study of the thermal shrinkage of polymer products.
ABSTRACT An optical surface measurement system, which is capable of measuring transient surface s... more ABSTRACT An optical surface measurement system, which is capable of measuring transient surface shape, has been developed by using a high-speed digital camera. The system is based on the grating projection and Fourier transform technique. A calibration procedure is developed to allow the system to generate Cartesian coordinates directly, which are with respect to a fixed coordinate system in 3-D space. The measurement accuracy (±50 μm) is defined and verified as the maximum error between measured values and the known values of standard objects both flat and curved. The camera and a grating projector are mounted into a portable sensor head to allow in situ measurements. In addition, external force or pressure signals can be correlated with each measurement through a device called the multi-channel data link. The system is capable of digitizing a 3-D curved surface into an array of points with known xyz coordinates at a sampling rate from 30 to 1000 Hz. As an application, the system is used to measure the transient surface shape during a polymer membrane inflation test. The measurement results along with the pressure information provide an approach to determine the material parameters used in different material models.
This paper introduces a new methodology from which better material parameters may be identified. ... more This paper introduces a new methodology from which better material parameters may be identified. The method will account for both non-repeatability of test data (by means of signal-to-noise weighting factors) and potential discrepancies between material parameters in different deformation modes (by means of a multi-objective optimization process). Finally, to show the application of the method, test data for a 2×2 twill weave fabric from different modes (namely, uniaxial extension and bias-extension) are selected to identify the model parameters of an orthotropic material model. The procedure may be applied to other material models and applications.
Journal of Engineering Materials and Technology, 2004
Engineering test data occasionally violate assumptions underlying standard material model identif... more Engineering test data occasionally violate assumptions underlying standard material model identification. Consequently, one has to apply appropriate remedies with respect to each violation to enhance the reliability of identified material parameters. This paper generalizes the use ...
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