Glenn Daehn | The Ohio State University (original) (raw)
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Papers by Glenn Daehn
The importance of well-developed constitutive models for predicting deformation behavior of mater... more The importance of well-developed constitutive models for predicting deformation behavior of materials at high strain rates cannot be overstated. The study and development of these constitutive models is pertinent to several fields, yet the test methods utilized to probe this high strain-rate realm are limited in both number and standardization. In an effort to augment current high rate tests, new technologies have been leveraged to revive an old, under-utilized test method – the axisymmetric expanding ring. The combination of Photon Doppler Velocimetry (PDV) and one of several ring launch techniques allows the successful testing and instrumentation of samples loaded in tension without wave effects at strain rates exceeding 10 s. Design and construction of the embodiment of this test at OSU, dubbed the Fully Instrumented Ring Expansion (FIRE) system, will be discussed. The key difficulties to implementation of the test are examined, along with our efforts to overcome them and prelimi...
Journal of Materials Processing Technology, 2014
Journal of Materials Engineering and Performance, 2013
ABSTRACT A previous study on electromagnetic forming (EM) hemming technology carried out in TECNA... more ABSTRACT A previous study on electromagnetic forming (EM) hemming technology carried out in TECNALIA showed the real capability of this high speed deformation method to produce quality hemmed parts (Jimbert et al., J. Mater. Process. Technol. 211:916–924, 2011). Continuing with the development of this promising new application for the EM technology, some new experiments were run. The objective of this study is to focus on the critical processing factors that affect the final quality of the electromagnetically hemmed parts. For this purpose, an experimental plan was designed changing different input parameters and output quality parameters measured to quantify the results. The flange height limit was obtained for the studied experimental setup and was established at 10 mm. The bending radius and the gap between the inner and the outer part have to be keep to the minimum to increase final quality. In parallel to the physical experiments, EM hemming simulations were carried out using an EM loose coupling simulation method. An EM hemming process simulation of a circular whole part was carried out using shell elements. Results were compared with cross section simulations of the hemmed union using solid elements in order to analyze the importance of the type of element used for EM hemming simulation. Simulations revealed that solid elements reproduce quality aspects better than shell elements.
Journal of Materials Engineering and Performance, 2007
Journal of Manufacturing Science and Engineering, 2007
High velocity electromagnetic forming can lead to better formability along with additional benefi... more High velocity electromagnetic forming can lead to better formability along with additional benefits. The spatial distribution of forming pressure in electromagnetic forming can be controlled by the configuration of the actuator. A new type of actuator is discussed which ...
Journal of Endodontics, 2006
Journal of Endodontics, 2005
International Journal of Fracture, 2010
Communications in Numerical Methods in Engineering, 1994
Earth and Planetary Science Letters, 2011
Composites Engineering, 1993
Acta Materialia, 1996
The uniaxial deformation properties of an alumina/aluminum composite where both phases are contin... more The uniaxial deformation properties of an alumina/aluminum composite where both phases are continuous have been studied both experimentally and analytically using the Finite Element (FE) method. The analytical and experimental work have shown the material to behave in a nearly bilinear manner defined by the Young's modulus and an elastic-plastic modulus. The FE modeling has shown good predictive capability in
Acta Materialia, 2012
ABSTRACT Mechanically alloyed, nanostructured ferritic steels represent a class of alloys that ca... more ABSTRACT Mechanically alloyed, nanostructured ferritic steels represent a class of alloys that can display high resistance to radiation and creep deformation, which are derived from the presence of nanoclusters, precipitates and solute segregation to the grain boundaries. The creep responses for a 14YWT nanostructured ferritic steel were measured over a range of temperatures and stress levels. The stress exponent was observed to vary non-linearly with applied stress; stress exponents were found to decrease with decreasing stress approaching unity at low stress. Transmission electron microscopy studies clearly demonstrated that creep deformation proceeds by a dislocation glide within nanoscale grains and that glide dislocations are attracted to and pinned by nanoclusters. In light of these observations, a new model of the creep response, inspired by the Kocks-Argon-Ashby model, is developed to explain the low creep rates and small stress exponents that are exhibited by these alloys.
Acta Materialia, 1996
ABSTRACT
Acta Materialia, 1996
ABSTRACT
Acta Materialia, 2001
ABSTRACT
The importance of well-developed constitutive models for predicting deformation behavior of mater... more The importance of well-developed constitutive models for predicting deformation behavior of materials at high strain rates cannot be overstated. The study and development of these constitutive models is pertinent to several fields, yet the test methods utilized to probe this high strain-rate realm are limited in both number and standardization. In an effort to augment current high rate tests, new technologies have been leveraged to revive an old, under-utilized test method – the axisymmetric expanding ring. The combination of Photon Doppler Velocimetry (PDV) and one of several ring launch techniques allows the successful testing and instrumentation of samples loaded in tension without wave effects at strain rates exceeding 10 s. Design and construction of the embodiment of this test at OSU, dubbed the Fully Instrumented Ring Expansion (FIRE) system, will be discussed. The key difficulties to implementation of the test are examined, along with our efforts to overcome them and prelimi...
Journal of Materials Processing Technology, 2014
Journal of Materials Engineering and Performance, 2013
ABSTRACT A previous study on electromagnetic forming (EM) hemming technology carried out in TECNA... more ABSTRACT A previous study on electromagnetic forming (EM) hemming technology carried out in TECNALIA showed the real capability of this high speed deformation method to produce quality hemmed parts (Jimbert et al., J. Mater. Process. Technol. 211:916–924, 2011). Continuing with the development of this promising new application for the EM technology, some new experiments were run. The objective of this study is to focus on the critical processing factors that affect the final quality of the electromagnetically hemmed parts. For this purpose, an experimental plan was designed changing different input parameters and output quality parameters measured to quantify the results. The flange height limit was obtained for the studied experimental setup and was established at 10 mm. The bending radius and the gap between the inner and the outer part have to be keep to the minimum to increase final quality. In parallel to the physical experiments, EM hemming simulations were carried out using an EM loose coupling simulation method. An EM hemming process simulation of a circular whole part was carried out using shell elements. Results were compared with cross section simulations of the hemmed union using solid elements in order to analyze the importance of the type of element used for EM hemming simulation. Simulations revealed that solid elements reproduce quality aspects better than shell elements.
Journal of Materials Engineering and Performance, 2007
Journal of Manufacturing Science and Engineering, 2007
High velocity electromagnetic forming can lead to better formability along with additional benefi... more High velocity electromagnetic forming can lead to better formability along with additional benefits. The spatial distribution of forming pressure in electromagnetic forming can be controlled by the configuration of the actuator. A new type of actuator is discussed which ...
Journal of Endodontics, 2006
Journal of Endodontics, 2005
International Journal of Fracture, 2010
Communications in Numerical Methods in Engineering, 1994
Earth and Planetary Science Letters, 2011
Composites Engineering, 1993
Acta Materialia, 1996
The uniaxial deformation properties of an alumina/aluminum composite where both phases are contin... more The uniaxial deformation properties of an alumina/aluminum composite where both phases are continuous have been studied both experimentally and analytically using the Finite Element (FE) method. The analytical and experimental work have shown the material to behave in a nearly bilinear manner defined by the Young's modulus and an elastic-plastic modulus. The FE modeling has shown good predictive capability in
Acta Materialia, 2012
ABSTRACT Mechanically alloyed, nanostructured ferritic steels represent a class of alloys that ca... more ABSTRACT Mechanically alloyed, nanostructured ferritic steels represent a class of alloys that can display high resistance to radiation and creep deformation, which are derived from the presence of nanoclusters, precipitates and solute segregation to the grain boundaries. The creep responses for a 14YWT nanostructured ferritic steel were measured over a range of temperatures and stress levels. The stress exponent was observed to vary non-linearly with applied stress; stress exponents were found to decrease with decreasing stress approaching unity at low stress. Transmission electron microscopy studies clearly demonstrated that creep deformation proceeds by a dislocation glide within nanoscale grains and that glide dislocations are attracted to and pinned by nanoclusters. In light of these observations, a new model of the creep response, inspired by the Kocks-Argon-Ashby model, is developed to explain the low creep rates and small stress exponents that are exhibited by these alloys.
Acta Materialia, 1996
ABSTRACT
Acta Materialia, 1996
ABSTRACT
Acta Materialia, 2001
ABSTRACT