Manganin piezoresistive gauges have been extensively used in dynamic stress measurement for decades.It is noted,however,that when used to measure transverse stresses,considerable strain effect is caused as the consequ...Manganin piezoresistive gauges have been extensively used in dynamic stress measurement for decades.It is noted,however,that when used to measure transverse stresses,considerable strain effect is caused as the consequence of change of electrical resistance resulted from bending of wires in the longitudinal-strain-experiencing sensing element of the gauge,a phenomenon discussed in this paper theoretically as well as experimentally.This effect yields unwanted signals to blend with output piezoresistive signals and is not negligible,hence decreases measurement accuracy sizably if not properly handled.To overcome this drawback,a new type of manganin transverse piezoresistive gauge has been developed by authors of this paper,which can reduce the resistance increment to acceptable low level so as to effectively bring the adverse effect under control.展开更多
A new kind of thin film manganin aray gauge is fabricated by adopting a new sensorfabrication technique.The sensitive materials (manganin thin films) are first deposited by magnetronsputtering on fused silica substrat...A new kind of thin film manganin aray gauge is fabricated by adopting a new sensorfabrication technique.The sensitive materials (manganin thin films) are first deposited by magnetronsputtering on fused silica substrates,and then covered by a layer of SiO_2 thin films by electron beamevaporation.Based on impedance match method of 'back configuration',the highest pressure measuredin Al target is 51.68 Gpa,the highest pressure in SiO_2 package is 35.396 Gpa and the piezoresistancecoefficient k is 0.026 Gpa^(-1).The upper limit and measure precision of sensor is improved.展开更多
Accurately predicting reactive flow is a challenge when characterizing an explosive under external shock stimuli as the shock initiation time is on the order of a microsecond.The present study constructs a new Ignitio...Accurately predicting reactive flow is a challenge when characterizing an explosive under external shock stimuli as the shock initiation time is on the order of a microsecond.The present study constructs a new Ignition-Growth reaction rate model,which can describe the shock initiation processes of explosives with different initial densities,particle sizes and loading pressures by only one set of model parameters.Compared with the Lee-Tarver reaction rate model,the new Ignition-Growth reaction rate model describes better the shock initiation process of explosives and requires fewer model parameters.Moreover,the shock initiation of a 2,4-Dinitroanisole(DNAN)-based melt-cast explosive RDA-2(DNAN/HMX(octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazoncine)/aluminum)are investigated both experimentally and numerically.A series of shock initiation experiments is performed with manganin piezoresistive pressure gauges and corresponding numerical simulations are carried out with the new Ignition-Growth reaction rate model.The RDA-2 explosive is found to have higher critical initiation pressure and lower shock sensitivity than traditional explosives(such as the Comp.B explosive).The calibrated reaction rate model parameters of RDA-2 could provide numerical basis for its further application.展开更多
基金Sponsored by the National Natural Science of China(10472014)
文摘Manganin piezoresistive gauges have been extensively used in dynamic stress measurement for decades.It is noted,however,that when used to measure transverse stresses,considerable strain effect is caused as the consequence of change of electrical resistance resulted from bending of wires in the longitudinal-strain-experiencing sensing element of the gauge,a phenomenon discussed in this paper theoretically as well as experimentally.This effect yields unwanted signals to blend with output piezoresistive signals and is not negligible,hence decreases measurement accuracy sizably if not properly handled.To overcome this drawback,a new type of manganin transverse piezoresistive gauge has been developed by authors of this paper,which can reduce the resistance increment to acceptable low level so as to effectively bring the adverse effect under control.
文摘A new kind of thin film manganin aray gauge is fabricated by adopting a new sensorfabrication technique.The sensitive materials (manganin thin films) are first deposited by magnetronsputtering on fused silica substrates,and then covered by a layer of SiO_2 thin films by electron beamevaporation.Based on impedance match method of 'back configuration',the highest pressure measuredin Al target is 51.68 Gpa,the highest pressure in SiO_2 package is 35.396 Gpa and the piezoresistancecoefficient k is 0.026 Gpa^(-1).The upper limit and measure precision of sensor is improved.
基金supported by the Innovative Group of Material and Structure Impact Dynamics(Grant No.11521062)。
文摘Accurately predicting reactive flow is a challenge when characterizing an explosive under external shock stimuli as the shock initiation time is on the order of a microsecond.The present study constructs a new Ignition-Growth reaction rate model,which can describe the shock initiation processes of explosives with different initial densities,particle sizes and loading pressures by only one set of model parameters.Compared with the Lee-Tarver reaction rate model,the new Ignition-Growth reaction rate model describes better the shock initiation process of explosives and requires fewer model parameters.Moreover,the shock initiation of a 2,4-Dinitroanisole(DNAN)-based melt-cast explosive RDA-2(DNAN/HMX(octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazoncine)/aluminum)are investigated both experimentally and numerically.A series of shock initiation experiments is performed with manganin piezoresistive pressure gauges and corresponding numerical simulations are carried out with the new Ignition-Growth reaction rate model.The RDA-2 explosive is found to have higher critical initiation pressure and lower shock sensitivity than traditional explosives(such as the Comp.B explosive).The calibrated reaction rate model parameters of RDA-2 could provide numerical basis for its further application.
