An inherent strain method was applied to the welding deformation analysis of left girder of GM’s Buick’s chassis underframe assembly. Three models are used in the calculation. Model 1 takes into account the longitud...An inherent strain method was applied to the welding deformation analysis of left girder of GM’s Buick’s chassis underframe assembly. Three models are used in the calculation. Model 1 takes into account the longitudinal and transverse inherent strains; model 2 considers only longitudinal inherent strain; model 3 also takes into account the longitudinal and transverse inherent strains, but inherent strains are taken according to the function instead of the constant, for simulating the variation of the girder’s stiffness during welding process. The result shows the deformation of model 2 is less than that of the model 1, the error is less than 10% of the absolute displacement. So the longitudinal inherent strain is the main factor determining boxes-girder’s welding deformation. The deformation of model 3 is also less than that of the model 1, because the inherent strains of the model 3 are less than that of the model 1. At last, the welding deformation of the whole underframe was analyzed. The analysis results can be taken as references not only for the choices of welding sequence, welding parameters and fixture’s location, but also for welding deformation prediction of other car chassis.展开更多
To find the difference in dynamic characteristics between conventional monohull ship and wave penetrating catamaran (WPC), a WPC was taken as an object; its dynamic characteristics were computed by transfer matrix met...To find the difference in dynamic characteristics between conventional monohull ship and wave penetrating catamaran (WPC), a WPC was taken as an object; its dynamic characteristics were computed by transfer matrix method and finite element method respectively. According to the comparison of the nature frequency results and mode shape results, the fact that FEM method is more suitable to dynamic characteristics analysis of a WPC was pointed out, special features on dynamic characteristics of WPC were given, and some beneficial suggestions are proposed to optimize the strength of a WPC in design period.展开更多
On the basis of differently defined functions- than otherwise - for conjunction, disjunction and implication （＊）, we construct a formal system, as an axiomatic theory, on its three levels： propositional, predicate...On the basis of differently defined functions- than otherwise - for conjunction, disjunction and implication （＊）, we construct a formal system, as an axiomatic theory, on its three levels： propositional, predicate and arithmetical one, intended to be a formalizaton of identically false formulas. We argue somewhat in favor of such a system from the point of view of its meta theory （it is complete and consistent one）, of properties of duality, symmetry etc., as well as of a logic of a possible world.展开更多
Moral generalism and particularism are two positions in meta-ethics which have different views regarding the relation between moral thought and principles. By accepting this relationship, generalists emphasize the nec...Moral generalism and particularism are two positions in meta-ethics which have different views regarding the relation between moral thought and principles. By accepting this relationship, generalists emphasize the necessity of principles in decision making process, and claim that the rationality of moral thought depends on the provision of a suitable supply ofmoral principles. In contrast, particularists have rejected, or at least doubted, the existence of moral principles, and believe that the rationality of moral thought depends on recognizing special features of a case and relevant conditions. This is why, unlike generalists, they use case study method rather than syllogism in decision making process and moral judgment. Consequently, to support their view, particularists commonly resort to holism in the theory of reasons, while atomism is in support of generalism. To evaluate these two attitudes, this study surveys some arguments that particularists and generalists proposed to justify their view and criticize the rival＇s one, and also explains their positions concerning the epistemological and metaphysical role of moral principles and reasons. Finally, after evaluating their claims, the importance of both approaches in meta-ethics is stressed.展开更多
基金Shanghai Car Industry Science and Technology DevelopmentFoundation (No.2 3 2 8A)
文摘An inherent strain method was applied to the welding deformation analysis of left girder of GM’s Buick’s chassis underframe assembly. Three models are used in the calculation. Model 1 takes into account the longitudinal and transverse inherent strains; model 2 considers only longitudinal inherent strain; model 3 also takes into account the longitudinal and transverse inherent strains, but inherent strains are taken according to the function instead of the constant, for simulating the variation of the girder’s stiffness during welding process. The result shows the deformation of model 2 is less than that of the model 1, the error is less than 10% of the absolute displacement. So the longitudinal inherent strain is the main factor determining boxes-girder’s welding deformation. The deformation of model 3 is also less than that of the model 1, because the inherent strains of the model 3 are less than that of the model 1. At last, the welding deformation of the whole underframe was analyzed. The analysis results can be taken as references not only for the choices of welding sequence, welding parameters and fixture’s location, but also for welding deformation prediction of other car chassis.
文摘To find the difference in dynamic characteristics between conventional monohull ship and wave penetrating catamaran (WPC), a WPC was taken as an object; its dynamic characteristics were computed by transfer matrix method and finite element method respectively. According to the comparison of the nature frequency results and mode shape results, the fact that FEM method is more suitable to dynamic characteristics analysis of a WPC was pointed out, special features on dynamic characteristics of WPC were given, and some beneficial suggestions are proposed to optimize the strength of a WPC in design period.
文摘On the basis of differently defined functions- than otherwise - for conjunction, disjunction and implication （＊）, we construct a formal system, as an axiomatic theory, on its three levels： propositional, predicate and arithmetical one, intended to be a formalizaton of identically false formulas. We argue somewhat in favor of such a system from the point of view of its meta theory （it is complete and consistent one）, of properties of duality, symmetry etc., as well as of a logic of a possible world.
文摘Moral generalism and particularism are two positions in meta-ethics which have different views regarding the relation between moral thought and principles. By accepting this relationship, generalists emphasize the necessity of principles in decision making process, and claim that the rationality of moral thought depends on the provision of a suitable supply ofmoral principles. In contrast, particularists have rejected, or at least doubted, the existence of moral principles, and believe that the rationality of moral thought depends on recognizing special features of a case and relevant conditions. This is why, unlike generalists, they use case study method rather than syllogism in decision making process and moral judgment. Consequently, to support their view, particularists commonly resort to holism in the theory of reasons, while atomism is in support of generalism. To evaluate these two attitudes, this study surveys some arguments that particularists and generalists proposed to justify their view and criticize the rival＇s one, and also explains their positions concerning the epistemological and metaphysical role of moral principles and reasons. Finally, after evaluating their claims, the importance of both approaches in meta-ethics is stressed.
