รบกวนเพื่อนๆพี่ๆน้องๆ ช่วยแปลบทความนี้ให้หน่อยครับ เกี่ยวกับเซรามิกส์ครับ
Modelling Pressure Patterns and Failure of Ceraimic Cake During Drying Within Plaster Mould
Abstract:
Hydraulic pressure created by mould’s suction within a ceramic cakeformed out of slipwater has been simulated over its length and time on the analogyof a modified thermal flow theory by diffusion-convection equation. The simulation results show that the pressure flow through the particulate medium ofthe cake, which also moves could lead to pressure accumulation with time in thelayers close to the mould-cake interface and consequently develop internal stresses of tensile nature in the region. The results further indicate that the particulatecohesion of the cake would be disrupted at 0.1 cm position at 7.1 minutes as theresultant stress could exceed the green item’s tensile strength.
introduction
In recent decades, a number of works have been reported on the solid-liquid separation problems in
ceramics.1-3 These attempt to put forward relationships between flow parameters and the structure of filter cake developed from slip or suspensions. One of the major concerns that has prompted these studies is the growth of defects in green items which subsequently contribute to the item failure. Direct studies on failure however have remained very limited. The importance of the problem is due to the fact that failure results in wastage of enormous cost and time in industry. There is very limited literature available on line. One of the very few works proposed a quantitative theory on cracks and wrap of simply shaped semisaturated clay items. 4 On the analogy of thermal stress theory it was shown that the stresses within the body as it dries up can be calculated if water flow is assumed to be similar to the heat flow process. The theory however lacked experimental confirmation. Another work was on the cracks in extruded green products of heavy clay.5 The causes of failure were identified on experimental basis and the need to measure and model the failure 145 phenomena was emphasized. The work thus lacked a theoretical framework. The subject therefore has restricted theoretical or experimental basis. When experimental evidences are limited, mathematical models may provide an alternative way for theoretical pursuit of the problem. The advantage of such an exercise is that a parameter can be simulated on computer under a set of boundary conditions and more importantly the variability in the process parameter can be studied numerically over space and time without resort to experimentation.
CONCLUSIONS
A mathematical model along with a simple failure criterion for green items in the soft plastic condition,
formed out of slipwater in mould has been developed under simplified assumption to explain
the physical mechanism of failure as item leather hardens. The internal tension within cake item disrupts
its cohesion as the tension exceeds the item strength. The model when tested with some published
data from ceramics and allied sciences theoretically replicates the patterns of hydraulic pressure at different time and positions within cake.
ช่วยแปลบทความนี้ให้หน่อยครับ
Modelling Pressure Patterns and Failure of Ceraimic Cake During Drying Within Plaster Mould
Abstract:
Hydraulic pressure created by mould’s suction within a ceramic cakeformed out of slipwater has been simulated over its length and time on the analogyof a modified thermal flow theory by diffusion-convection equation. The simulation results show that the pressure flow through the particulate medium ofthe cake, which also moves could lead to pressure accumulation with time in thelayers close to the mould-cake interface and consequently develop internal stresses of tensile nature in the region. The results further indicate that the particulatecohesion of the cake would be disrupted at 0.1 cm position at 7.1 minutes as theresultant stress could exceed the green item’s tensile strength.
introduction
In recent decades, a number of works have been reported on the solid-liquid separation problems in
ceramics.1-3 These attempt to put forward relationships between flow parameters and the structure of filter cake developed from slip or suspensions. One of the major concerns that has prompted these studies is the growth of defects in green items which subsequently contribute to the item failure. Direct studies on failure however have remained very limited. The importance of the problem is due to the fact that failure results in wastage of enormous cost and time in industry. There is very limited literature available on line. One of the very few works proposed a quantitative theory on cracks and wrap of simply shaped semisaturated clay items. 4 On the analogy of thermal stress theory it was shown that the stresses within the body as it dries up can be calculated if water flow is assumed to be similar to the heat flow process. The theory however lacked experimental confirmation. Another work was on the cracks in extruded green products of heavy clay.5 The causes of failure were identified on experimental basis and the need to measure and model the failure 145 phenomena was emphasized. The work thus lacked a theoretical framework. The subject therefore has restricted theoretical or experimental basis. When experimental evidences are limited, mathematical models may provide an alternative way for theoretical pursuit of the problem. The advantage of such an exercise is that a parameter can be simulated on computer under a set of boundary conditions and more importantly the variability in the process parameter can be studied numerically over space and time without resort to experimentation.
CONCLUSIONS
A mathematical model along with a simple failure criterion for green items in the soft plastic condition,
formed out of slipwater in mould has been developed under simplified assumption to explain
the physical mechanism of failure as item leather hardens. The internal tension within cake item disrupts
its cohesion as the tension exceeds the item strength. The model when tested with some published
data from ceramics and allied sciences theoretically replicates the patterns of hydraulic pressure at different time and positions within cake.