Geomaterials are known to be non-associated materials. Granular soils therefore exhibit a variety of failure modes, with diffuse or localized kinematical patterns. In fact, the notion of failure itself can be confusin...Geomaterials are known to be non-associated materials. Granular soils therefore exhibit a variety of failure modes, with diffuse or localized kinematical patterns. In fact, the notion of failure itself can be confusing with regard to granular soils, because it is not associated with an obvious phenomenology. In this study, we built a proper framework, using the second-order work theory, to describe some failure modes in geomaterials based on energy conservation. The occurrence of failure is defined by an abrupt increase in kinetic energy. The increase in kinetic energy from an equilibrium state, under incremental loading, is shown to be equal to the difference between the external second-order work,involving the external loading parameters, and the internal second-order work, involving the constitutive properties of the material. When a stress limit state is reached, a certain stress component passes through a maximum value and then may decrease. Under such a condition, if a certain additional external loading is applied, the system fails, sharply increasing the strain rate. The internal stress is no longer able to balance the external stress, leading to a dynamic response of the specimen. As an illustration, the theoretical framework was applied to the well-known undrained triaxial test for loose soils. The influence of the loading control mode was clearly highlighted. It is shown that the plastic limit theory appears to be a particular case of this more general second-order work theory. When the plastic limit condition is met, the internal second-order work is nil. A class of incremental external loadings causes the kinetic energy to increase dramatically, leading to the sudden collapse of the specimen, as observed in laboratory.展开更多
Under the combined effects of inventory-level-dependent demand(ILDD)and trade credit,the retailer is able to order more quantities to stimulate market demand.However,from the supplier's perspective,two important i...Under the combined effects of inventory-level-dependent demand(ILDD)and trade credit,the retailer is able to order more quantities to stimulate market demand.However,from the supplier's perspective,two important issues are lacking sufficient attention.First,during the credit period,the retailer's higher order quantities imply increases in both the retailer's account payable and the supplier's opportunity cost of capital.Second,given the supplier's fixed production rate,the increased market demand may drive the capacity utilization to be variable.Thus,by formulating a supplier-dominated system,this paper incorporates trade credit limit(TCL)to address its effects on optimal policies vis-a-vis the item with ILDD.Specifically,three indicators can be proposed to reveal which type of financing policy the retailer should choose.Moreover,based on TCL,the supplier can effectively manage the retailer's order quantity and the corresponding account payable.Additionally,the retailer's maximum allowable order quantity is developed to ensure that the supplier can supply the retailer's order quantity on time.Furthermore,when the effects of ILDD become more significant,the manufacturer will reduce the maximum allowable order quantity to control the retailer's order incentive.展开更多
基金the French Research Network Me Ge (Multiscale and Multiphysics Couplings in Geo-environmental Mechanics GDR CNRS 3176/2340, 2008e2015) for having supported this work
文摘Geomaterials are known to be non-associated materials. Granular soils therefore exhibit a variety of failure modes, with diffuse or localized kinematical patterns. In fact, the notion of failure itself can be confusing with regard to granular soils, because it is not associated with an obvious phenomenology. In this study, we built a proper framework, using the second-order work theory, to describe some failure modes in geomaterials based on energy conservation. The occurrence of failure is defined by an abrupt increase in kinetic energy. The increase in kinetic energy from an equilibrium state, under incremental loading, is shown to be equal to the difference between the external second-order work,involving the external loading parameters, and the internal second-order work, involving the constitutive properties of the material. When a stress limit state is reached, a certain stress component passes through a maximum value and then may decrease. Under such a condition, if a certain additional external loading is applied, the system fails, sharply increasing the strain rate. The internal stress is no longer able to balance the external stress, leading to a dynamic response of the specimen. As an illustration, the theoretical framework was applied to the well-known undrained triaxial test for loose soils. The influence of the loading control mode was clearly highlighted. It is shown that the plastic limit theory appears to be a particular case of this more general second-order work theory. When the plastic limit condition is met, the internal second-order work is nil. A class of incremental external loadings causes the kinetic energy to increase dramatically, leading to the sudden collapse of the specimen, as observed in laboratory.
文摘Under the combined effects of inventory-level-dependent demand(ILDD)and trade credit,the retailer is able to order more quantities to stimulate market demand.However,from the supplier's perspective,two important issues are lacking sufficient attention.First,during the credit period,the retailer's higher order quantities imply increases in both the retailer's account payable and the supplier's opportunity cost of capital.Second,given the supplier's fixed production rate,the increased market demand may drive the capacity utilization to be variable.Thus,by formulating a supplier-dominated system,this paper incorporates trade credit limit(TCL)to address its effects on optimal policies vis-a-vis the item with ILDD.Specifically,three indicators can be proposed to reveal which type of financing policy the retailer should choose.Moreover,based on TCL,the supplier can effectively manage the retailer's order quantity and the corresponding account payable.Additionally,the retailer's maximum allowable order quantity is developed to ensure that the supplier can supply the retailer's order quantity on time.Furthermore,when the effects of ILDD become more significant,the manufacturer will reduce the maximum allowable order quantity to control the retailer's order incentive.
