Principal component analysis （PCA） is a useful tool in process fault detection, but offers little support on fault isolation. In this article, structured residual with strong isolation property is introduced. Althou...Principal component analysis （PCA） is a useful tool in process fault detection, but offers little support on fault isolation. In this article, structured residual with strong isolation property is introduced. Although it is easy to get the residual by transformation matrix in static process, unfortunately, it becomes hard in dynamic process under control loop. Therefore, partial dynamic PCA（PDPCA） is proposed to obtain structured residual and enhance the isolation ability of dynamic process monitoring, and a compound statistic is introduced to resolve the problem resulting from independent variables in every variable subset. Simulations on continuous stirred tank reactor （CSTR） show the effectiveness of the proposed method.展开更多
The hot deformation behavior of Fe-26Mn-6.2A1-0.05C steel was studied by experimental hot compression tests in the temperature range of 800-1050℃ and strain rate range of 0.01-30 s-1 on a Gleeble-3500 thermal simulat...The hot deformation behavior of Fe-26Mn-6.2A1-0.05C steel was studied by experimental hot compression tests in the temperature range of 800-1050℃ and strain rate range of 0.01-30 s-1 on a Gleeble-3500 thermal simulation machine.The microstructural evolution during the corresponding thermal process was observed in situ by confocal laser scanning microscopy.Electron backscattered diffraction and transmission electron microscopy analyses were carried out to observe the microstructural morphology before and after the hot deformation.Furthermore,interrupted compression tests were conducted to correlate the microstructural characteristics and softening mechanisms at different deformation stages.The results showed that hot compression tests of this steel were all carried out on a duplex matrix composed of austenite and fi-ferrite.As the deformation temperature increased from 800 to 1050℃,the volume fraction of austenite decreased from 70.9% to 44.0%,while that of 6-ferrite increased from 29.1% to 56.0%.Due to the different stress exponents（n）and apparent activation energies（Q）,the generated strain was mostly accommodated by δ-ferrite at the commencement of deformation,and then both dynamic recovery and dynamic recrystallization occurred earlier in δ-ferrite than in austenite.This interaction of strain partitioning and unsynchronized softening behavior caused an abnormal hot deformation behavior profile in the Fe-Mn-A1 duplex steel,such as yield-like behavior,peculiar work-hardening behavior,and dynamic softening behavior,which are influenced by not only temperature and strain rate but also by microstructural evolution.展开更多
基金the National Natural Science Foundation of China （No.60421002）.
文摘Principal component analysis （PCA） is a useful tool in process fault detection, but offers little support on fault isolation. In this article, structured residual with strong isolation property is introduced. Although it is easy to get the residual by transformation matrix in static process, unfortunately, it becomes hard in dynamic process under control loop. Therefore, partial dynamic PCA（PDPCA） is proposed to obtain structured residual and enhance the isolation ability of dynamic process monitoring, and a compound statistic is introduced to resolve the problem resulting from independent variables in every variable subset. Simulations on continuous stirred tank reactor （CSTR） show the effectiveness of the proposed method.
基金financially supported by the National Natural Science Foundation of China(No.51474031)
文摘The hot deformation behavior of Fe-26Mn-6.2A1-0.05C steel was studied by experimental hot compression tests in the temperature range of 800-1050℃ and strain rate range of 0.01-30 s-1 on a Gleeble-3500 thermal simulation machine.The microstructural evolution during the corresponding thermal process was observed in situ by confocal laser scanning microscopy.Electron backscattered diffraction and transmission electron microscopy analyses were carried out to observe the microstructural morphology before and after the hot deformation.Furthermore,interrupted compression tests were conducted to correlate the microstructural characteristics and softening mechanisms at different deformation stages.The results showed that hot compression tests of this steel were all carried out on a duplex matrix composed of austenite and fi-ferrite.As the deformation temperature increased from 800 to 1050℃,the volume fraction of austenite decreased from 70.9% to 44.0%,while that of 6-ferrite increased from 29.1% to 56.0%.Due to the different stress exponents（n）and apparent activation energies（Q）,the generated strain was mostly accommodated by δ-ferrite at the commencement of deformation,and then both dynamic recovery and dynamic recrystallization occurred earlier in δ-ferrite than in austenite.This interaction of strain partitioning and unsynchronized softening behavior caused an abnormal hot deformation behavior profile in the Fe-Mn-A1 duplex steel,such as yield-like behavior,peculiar work-hardening behavior,and dynamic softening behavior,which are influenced by not only temperature and strain rate but also by microstructural evolution.
