In the process of traditional aircraft structure design, repetitive manual modeling of aircraft wing box parts is time consuming. Meanwhile, it＇s difficult to update associated models when product design changes. Aim...In the process of traditional aircraft structure design, repetitive manual modeling of aircraft wing box parts is time consuming. Meanwhile, it＇s difficult to update associated models when product design changes. Aiming at solving these problems, a method for rapid modeling and updating associated models was put forward. Based on skeleton model, combining with the technology of template re-use, it makes aircraft wing box rapid modeling and correct updating possible. The detailed implementation process of the method was given, and a certain aircraft wing box was taken as an instance to verify the feasibility and effectiveness of this method.展开更多
By substituting rock skeleton modulus expressions into Gassmann approximate fluid equation, we obtain a seismic porosity inversion equation. However, conventional rock skeleton models and their expressions are quite d...By substituting rock skeleton modulus expressions into Gassmann approximate fluid equation, we obtain a seismic porosity inversion equation. However, conventional rock skeleton models and their expressions are quite different from each other, resuling in different seismic porosity inversion equations, potentially leading to difficulties in correctly applying them and evaluating their results. In response to this, a uniform relation with two adjusting parameters suitable for all rock skeleton models is established from an analysis and comparison of various conventional rock skeleton models and their expressions including the Eshelby-Walsh, Pride, Geertsma, Nur, Keys-Xu, and Krief models. By giving the two adjusting parameters specific values, different rock skeleton models with specific physical characteristics can be generated. This allows us to select the most appropriate rock skeleton model based on geological and geophysical conditions, and to develop more wise seismic porosity inversion. As an example of using this method for hydrocarbon prediction and fluid identification, we apply this improved porosity inversion, associated with rock physical data and well log data, to the ZJ basin. Research shows that the existence of an abundant hydrocarbon reservoir is dependent on a moderate porosity range, which means we can use the results of seismic porosity inversion to identify oil reservoirs and dry or water-saturated reservoirs. The seismic inversion results are closely correspond to well log porosity curves in the ZJ area, indicating that the uniform relations and inversion methods proposed in this paper are reliable and effective.展开更多
A finite element parametric modeling method of aircraft wing structures is proposed in this paper because of time-consuming characteristics of finite element analysis pre-processing. The main research is positioned du...A finite element parametric modeling method of aircraft wing structures is proposed in this paper because of time-consuming characteristics of finite element analysis pre-processing. The main research is positioned during the preliminary design phase of aircraft structures. A knowledge- driven system of fast finite element modeling is built. Based on this method, employing a template parametric technique, knowledge including design methods, rules, and expert experience in the process of modeling is encapsulated and a finite element model is established automatically, which greatly improves the speed, accuracy, and standardization degree of modeling. Skeleton model, geometric mesh model, and finite element model including finite element mesh and property data are established on parametric description and automatic update. The outcomes of research show that the method settles a series of problems of parameter association and model update in the process of finite element modeling which establishes a key technical basis for finite element parametric analysis and optimization design.展开更多
Lattice structures with excellent physical properties have attracted great research interest.In this paper,a novel volume parametric modeling method based on the skeleton model is proposed for the construction of thre...Lattice structures with excellent physical properties have attracted great research interest.In this paper,a novel volume parametric modeling method based on the skeleton model is proposed for the construction of threedimensional lattice structures.The skeleton model is divided into three types of nodes.And the corresponding algorithms are utilized to construct diverse types of volume parametric nodes.The unit-cell is assembled with distinct nodes according to the geometric features.The final lattice structure is created by the periodic arrangement of unit-cells.Several different types of volume parametric lattice structures are constructed to prove the stability and applicability of the proposed method.The quality is assessed in terms of the value of the Jacobian matrix.Moreover,the volume parametric lattice structures are tested with the isogeometric analysis to verify the feasibility of integration of modeling and simulation.展开更多
An accurate finite element （ FE） model was constructed to examine the hysteretic behavior of double-skin steel-concrete composite box （ DSCB） piers for further understanding the seismic performance of DSCB piers;...An accurate finite element （ FE） model was constructed to examine the hysteretic behavior of double-skin steel-concrete composite box （ DSCB） piers for further understanding the seismic performance of DSCB piers; where the local buckling behavior of steel tubes, the confinement of the in-filled concrete and the interface action between steel tube and in-filled concrete were considered. The accuracy of the proposed FE model was verified by the bidirectional cyclic loading test results. Based on the validated FE model, the effects of some key parameters, such as section width to steel thickness ratio, slenderness ratio, aspect ratio and axial load ratio on the hysteretic behavior of DSCB piers were investigated. Finally, the skeleton curve model of DSCB piers was proposed. The numerical simulation results reveal that the peak strength and elastic stiffness decrease with the increase of the section width to steel thickness ratio. Moreover, the increase of the slenderness ratio may result in a significant reduction in the peak strength and elastic stiffness while the ultimate displacement increases. The proposed skeleton curve model can be taken as a reference for seismic performance analyses of the DSCB piers.展开更多
The effect of recycled coarse aggregate on concrete compressive strength was investigated based on the concrete skeleton theory. For this purpose, 30 mix proportions of concrete with target cube compressive strength r...The effect of recycled coarse aggregate on concrete compressive strength was investigated based on the concrete skeleton theory. For this purpose, 30 mix proportions of concrete with target cube compressive strength ranging from 20 to 60 MPa were cast with normal coarse aggregate and recycled coarse aggregate from different strength parent concretes. Results of 28-d test show that the strength of different types of recycled aggregate affects the concrete strength obviously. The coarse aggregate added to mortar matrix plays a skeleton role and improves its compressive strength. The skeleton effect of coarse aggregate increases with the increasing strength of coarse aggregate, and normal coarse aggregate plays the highest, whereas the lowest concrete strength occurs when using the weak recycled coarse aggregate. There is a linear relationship between the concrete strength and the corresponding mortar matrix strength. Coarse aggregate skeleton formula is established, and values from experimental tests match the derived expressions.展开更多
In order to accelerate the product design and shorten the development cycle, the product design base on Top-Down and product level parametric design method. Based on the 2K-V type of product structure tree, the mappin...In order to accelerate the product design and shorten the development cycle, the product design base on Top-Down and product level parametric design method. Based on the 2K-V type of product structure tree, the mapping of the structure tree to the hierarchical skeleton feature tree is completed and the modeling of the~ product＇s 3D cascade skeleton is built with Pro/E skeleton Technology. The skeleton model is the basis of assembly, then to build the framework of the model＇s cascade constraints and to realize the whole model driven by the top skeleton parameters. The designers can build new models in the design of the similar structure through the rapid variant design of top skeleton parameters展开更多
To directly use a virtual surface model for action editing and movement control,a general method for creating virtual actor skeleton models and controlling movement is presented.The method includes judging borderlines...To directly use a virtual surface model for action editing and movement control,a general method for creating virtual actor skeleton models and controlling movement is presented.The method includes judging borderlines of the block virtual surface model,calculating the joints,confirming the above block,and using the block hierarchical layout to create the skeleton model.Then,according to the virtual actor model and movement restriction,the study focuses on the generation of movement animation using the key frame technique and smoothing movement technique by automatically adding animation and adjusting the actor’s pose by different weights on movement amplitude.Finally,movement control of the actor in the virtual environment is implemented by real-time control and path point control,which achieve a good result.展开更多
文摘In the process of traditional aircraft structure design, repetitive manual modeling of aircraft wing box parts is time consuming. Meanwhile, it＇s difficult to update associated models when product design changes. Aiming at solving these problems, a method for rapid modeling and updating associated models was put forward. Based on skeleton model, combining with the technology of template re-use, it makes aircraft wing box rapid modeling and correct updating possible. The detailed implementation process of the method was given, and a certain aircraft wing box was taken as an instance to verify the feasibility and effectiveness of this method.
基金supported by the National Nature Science Foundation of China(Grant No.41174114)Important National Science and Technology Specific Projects(Grant No.2011ZX05025-005-010)
文摘By substituting rock skeleton modulus expressions into Gassmann approximate fluid equation, we obtain a seismic porosity inversion equation. However, conventional rock skeleton models and their expressions are quite different from each other, resuling in different seismic porosity inversion equations, potentially leading to difficulties in correctly applying them and evaluating their results. In response to this, a uniform relation with two adjusting parameters suitable for all rock skeleton models is established from an analysis and comparison of various conventional rock skeleton models and their expressions including the Eshelby-Walsh, Pride, Geertsma, Nur, Keys-Xu, and Krief models. By giving the two adjusting parameters specific values, different rock skeleton models with specific physical characteristics can be generated. This allows us to select the most appropriate rock skeleton model based on geological and geophysical conditions, and to develop more wise seismic porosity inversion. As an example of using this method for hydrocarbon prediction and fluid identification, we apply this improved porosity inversion, associated with rock physical data and well log data, to the ZJ basin. Research shows that the existence of an abundant hydrocarbon reservoir is dependent on a moderate porosity range, which means we can use the results of seismic porosity inversion to identify oil reservoirs and dry or water-saturated reservoirs. The seismic inversion results are closely correspond to well log porosity curves in the ZJ area, indicating that the uniform relations and inversion methods proposed in this paper are reliable and effective.
基金supported by the National Natural Science Foundation (No.51075021)
文摘A finite element parametric modeling method of aircraft wing structures is proposed in this paper because of time-consuming characteristics of finite element analysis pre-processing. The main research is positioned during the preliminary design phase of aircraft structures. A knowledge- driven system of fast finite element modeling is built. Based on this method, employing a template parametric technique, knowledge including design methods, rules, and expert experience in the process of modeling is encapsulated and a finite element model is established automatically, which greatly improves the speed, accuracy, and standardization degree of modeling. Skeleton model, geometric mesh model, and finite element model including finite element mesh and property data are established on parametric description and automatic update. The outcomes of research show that the method settles a series of problems of parameter association and model update in the process of finite element modeling which establishes a key technical basis for finite element parametric analysis and optimization design.
基金supported by the National Nature Science Foundation of China under Grant No.52075340.
文摘Lattice structures with excellent physical properties have attracted great research interest.In this paper,a novel volume parametric modeling method based on the skeleton model is proposed for the construction of threedimensional lattice structures.The skeleton model is divided into three types of nodes.And the corresponding algorithms are utilized to construct diverse types of volume parametric nodes.The unit-cell is assembled with distinct nodes according to the geometric features.The final lattice structure is created by the periodic arrangement of unit-cells.Several different types of volume parametric lattice structures are constructed to prove the stability and applicability of the proposed method.The quality is assessed in terms of the value of the Jacobian matrix.Moreover,the volume parametric lattice structures are tested with the isogeometric analysis to verify the feasibility of integration of modeling and simulation.
基金The National Natural Science Foundation of China(No.51678141,51378112)the Open Fund from the National Engineering Laboratory for Technology of Geological Disaster Prevention in Land Transportation,Southwest Jiaotong University(No.SWJTUGGS-2014001)
文摘An accurate finite element （ FE） model was constructed to examine the hysteretic behavior of double-skin steel-concrete composite box （ DSCB） piers for further understanding the seismic performance of DSCB piers; where the local buckling behavior of steel tubes, the confinement of the in-filled concrete and the interface action between steel tube and in-filled concrete were considered. The accuracy of the proposed FE model was verified by the bidirectional cyclic loading test results. Based on the validated FE model, the effects of some key parameters, such as section width to steel thickness ratio, slenderness ratio, aspect ratio and axial load ratio on the hysteretic behavior of DSCB piers were investigated. Finally, the skeleton curve model of DSCB piers was proposed. The numerical simulation results reveal that the peak strength and elastic stiffness decrease with the increase of the section width to steel thickness ratio. Moreover, the increase of the slenderness ratio may result in a significant reduction in the peak strength and elastic stiffness while the ultimate displacement increases. The proposed skeleton curve model can be taken as a reference for seismic performance analyses of the DSCB piers.
基金Supported by the National Mega-Project of Key Technology R&D Program in the 11th Five-Year Plan of China (No.2006BAJ04A04)the Education Department of Liaoning Province, China (No. 2008282)
文摘The effect of recycled coarse aggregate on concrete compressive strength was investigated based on the concrete skeleton theory. For this purpose, 30 mix proportions of concrete with target cube compressive strength ranging from 20 to 60 MPa were cast with normal coarse aggregate and recycled coarse aggregate from different strength parent concretes. Results of 28-d test show that the strength of different types of recycled aggregate affects the concrete strength obviously. The coarse aggregate added to mortar matrix plays a skeleton role and improves its compressive strength. The skeleton effect of coarse aggregate increases with the increasing strength of coarse aggregate, and normal coarse aggregate plays the highest, whereas the lowest concrete strength occurs when using the weak recycled coarse aggregate. There is a linear relationship between the concrete strength and the corresponding mortar matrix strength. Coarse aggregate skeleton formula is established, and values from experimental tests match the derived expressions.
文摘In order to accelerate the product design and shorten the development cycle, the product design base on Top-Down and product level parametric design method. Based on the 2K-V type of product structure tree, the mapping of the structure tree to the hierarchical skeleton feature tree is completed and the modeling of the~ product＇s 3D cascade skeleton is built with Pro/E skeleton Technology. The skeleton model is the basis of assembly, then to build the framework of the model＇s cascade constraints and to realize the whole model driven by the top skeleton parameters. The designers can build new models in the design of the similar structure through the rapid variant design of top skeleton parameters
基金This work was supported by the Southeast University Fund(No.9222001286).
文摘To directly use a virtual surface model for action editing and movement control,a general method for creating virtual actor skeleton models and controlling movement is presented.The method includes judging borderlines of the block virtual surface model,calculating the joints,confirming the above block,and using the block hierarchical layout to create the skeleton model.Then,according to the virtual actor model and movement restriction,the study focuses on the generation of movement animation using the key frame technique and smoothing movement technique by automatically adding animation and adjusting the actor’s pose by different weights on movement amplitude.Finally,movement control of the actor in the virtual environment is implemented by real-time control and path point control,which achieve a good result.
