The effect of additives containing rare earth elements La and Y on the structure and mechanical property of ceramic-lined composite pipe was studied in presence of centrifugation. The fracture and shearing strength of...The effect of additives containing rare earth elements La and Y on the structure and mechanical property of ceramic-lined composite pipe was studied in presence of centrifugation. The fracture and shearing strength of ceramic-lined composite pipe containing different additives were measured and analyzed through the fracture and shearing strength experiments. The distribution of shear stress on the interface of ceramic layer and the pipe is computed by finite element method.展开更多
Oscillating heat pipes (OHPs) are very promising cooling devices. Their heat transfer performance is af- fected by many factors, and the form of the relationship between the performance and the factors is complex and ...Oscillating heat pipes (OHPs) are very promising cooling devices. Their heat transfer performance is af- fected by many factors, and the form of the relationship between the performance and the factors is complex and non-linear. In this paper, the effects of charging ratio, inclination angle, and heat input and their interaction effects on heat transfer performance of a looped copper-water OHP are analyzed. First, suppose that the relationship between the response and the variables approximates a second-order model. And use the central composite design to arrange the ex- periment. Then, the method of least squares is used to estimate the parameters in the second-order model. Finally, multi- variate variance analysis is used to analyze the model. The results show that the assumption is right, that is to say, the re- lationship is well modeled by a second-order function. Among the three main effect variables, the effect of inclination angle is the most significant, but their interaction effects are not significant. In the range of the considered factors, both the optimum charging ratio and the optimum inclination angle increase as the heating water flow rate increases.展开更多
Based on the advantages of perforated ventilation characteristic of perforated ventilation pipe embankment and large porosity of blocky stone embankment, composite embankment with ventilation pipe and blocky stone is ...Based on the advantages of perforated ventilation characteristic of perforated ventilation pipe embankment and large porosity of blocky stone embankment, composite embankment with ventilation pipe and blocky stone is more efficient to protect the underlying permafrost. The temperature fields and cooling effect of composite embankment with air doors are simulated by examining the effects of holes＇ position drilled in the pipe, diameter in pipe and density of holes. It is shown that the underlying permafrost temperature obviously reduces by composite methods, the location of 0℃ isotherm raises significantly, especially permafrost temperature under the center and shoulder of embankment reduces more quickly, the composite embankment with holes drilled in the lower side of pipe is the most efficient, the increase of diameter has a slight influence on the 0℃ isotherm＇s raising, and the density of holes slightly influences the raising of 0℃ isotherm.展开更多
<div style="text-align:justify;"> In view of the serious lack and lag of the test and evaluation technology of non-metallic composite continuous pipe, and focusing on the characteristics of the applica...<div style="text-align:justify;"> In view of the serious lack and lag of the test and evaluation technology of non-metallic composite continuous pipe, and focusing on the characteristics of the application of non-metallic composite continuous pipe in oil field, this paper discusses a series of new full-scale test and evaluation technologies for accurately evaluating the product quality and practical application performance of non-metallic composite continuous pipe, which effectively solves the major technical problem that the new products of non-metallic pipe cannot be accurately evaluated. Based on the characteristics of the application of non-metallic composite continuous pipe in oil field, a series of new full-scale test evaluation technologies which can accurately evaluate the product quality and practical application performance of non-metallic pipe are designed through a large number of tests. The test and evaluation technology can accurately evaluate the key performance of high and low pressure cycle, high and low temperature cycle, gas permeability resistance, minimum bending radius etc. It provides a scientific evaluation basis for the standardized application of non-metallic continuous pipe and a reliable quality control method for the selection of products in oil field. </div>展开更多
The PE-Al-PE composite pipe is a multiplayer pipe t hat is composed of PE (polyethylene) and Aluminum. Al is inlayed the inner PE la yer and the outer PE layer. In the producing technological process of this kind of p...The PE-Al-PE composite pipe is a multiplayer pipe t hat is composed of PE (polyethylene) and Aluminum. Al is inlayed the inner PE la yer and the outer PE layer. In the producing technological process of this kind of pipe the bend forming of Al belt to tube is very important. It is the bend fo rming dies that are used in the process of producing PE-Al-PE pipe that is stu died in this article. To make a elaborate division, these dies can be classified as bending dies and forming dies here. In this paper, the designation of bendin g dies and forming dies that are used in producing technological process of PE- Al-PE pipe is put forward. The process starts from a coil of Al belt, in the ac tion of pulling force, passes between several bending dies to change its shape. The first step is to change Al belt to U shape. A couple of rolling wheels can b e used to shape the Al belt. The Al belt goes between the two rolling wheels, dr ives the wheels, at the same time is formed as the shape of the rolling wheels. Considering of the factors such as spring of the bend Al belt, frictional force between Al and the die, bending force needed to bend Al belt, etc., it must be s haped gradually into U by several dies. The designation of these dies has been g iven in this paper. The next step is to forming the U shape into a circle. The U shape Al belt goes through a round that is formed with a four-roller die, and then is shaped to a circle. Because the latter procedure requires the Al circle has a laminated area to be ultrasonic welded, this die must be designed to let t he two edges of the circle belt to be piled up to a definite width. But except f or the laminated area the other of the circle should be as round as possible. So the four rollers are not the same. The calculation and designation of the rolle rs of this four-roller die has also been given. The designation of the roller w hich is supposed to leave a gap to let the two edges of the circle belt to be pi led up is to make a fine rotation of an original circle. Then calculates the cen ter of the rotated arc and defines the arc completely. The designation method of the other rollers has also been given in this paper.展开更多
Polyethylene-steel Composite Pipes is widely used in conveying corrosive media occasions,but the pipe may lose effectiveness in the process of transporting hot and cold media,so the research of stress distribution and...Polyethylene-steel Composite Pipes is widely used in conveying corrosive media occasions,but the pipe may lose effectiveness in the process of transporting hot and cold media,so the research of stress distribution and variation in polyethylene-steel composite pipes is very necessary.This article first assume that a thin adhesive layer is in between the polyethylene and steel,the adhesive layer along the axial shear stress is the major cause of the polyethylene layer and the steel pipe off sticky.Secondly,we use a method of finite element to computer simulation by ANSYS,and verify initial assumptions.Finally,based on simulation data,we analyse the adhesive layer stress distribution and the variation with different parameters to change.Through the above research,preliminarily summarize the variation and distribution of interlaminar stress,and provide technical support for future design and process improvement of polyethylenesteel pipe.展开更多
Urban sewer pipes are a vital infrastructure in modern cities,and their defects must be detected in time to prevent potential malfunctioning.In recent years,to relieve the manual efforts by human experts,models based ...Urban sewer pipes are a vital infrastructure in modern cities,and their defects must be detected in time to prevent potential malfunctioning.In recent years,to relieve the manual efforts by human experts,models based on deep learning have been introduced to automatically identify potential defects.However,these models are insufficient in terms of dataset complexity,model versatility and performance.Our work addresses these issues with amulti-stage defect detection architecture using a composite backbone Swin Transformer.Themodel based on this architecture is trained using a more comprehensive dataset containingmore classes of defects.By ablation studies on the modules of combined backbone Swin Transformer,multi-stage detector,test-time data augmentation and model fusion,it is revealed that they all contribute to the improvement of detection accuracy from different aspects.The model incorporating all these modules achieves the mean Average Precision(mAP)of 78.6% at an Intersection over Union(IoU)threshold of 0.5.This represents an improvement of 14.1% over the ResNet50 Faster Region-based Convolutional Neural Network(R-CNN)model and a 6.7% improvement over You Only Look Once version 6(YOLOv6)-large,the highest in the YOLO methods.In addition,for other defect detection models for sewer pipes,although direct comparison with themis infeasible due to the unavailability of their private datasets,our results are obtained from a more comprehensive dataset and have superior generalization capabilities.展开更多
A set of serf-developed apparatus for foundation physical model were utilized to conduct model tests of the multi-element composite foundation with a steel pipe pile and several gravel piles. Some load-bearing charact...A set of serf-developed apparatus for foundation physical model were utilized to conduct model tests of the multi-element composite foundation with a steel pipe pile and several gravel piles. Some load-bearing characteristics of the multi-element Composite foundation, including the curves of foundation settlement, stresses of piles, pile-soil stress ratio, and load-sharing ratio of piles and soil, were obtained to study its working performances in silty sand soil. The experimental results revealed that the multi-element composite foundation with steel pipe pile and gravel pile contributed more than the gravel pile composite foundation in improving the bearing capacity of the silty fine sand.展开更多
Polyethylene/aluminum/polyethylene(PAP)composite pipe has the advantages of corrosion resistance,limited joints and convenient installation.We started to use the PAP pipe in fuel gas conveyance 21 years ago.It has exc...Polyethylene/aluminum/polyethylene(PAP)composite pipe has the advantages of corrosion resistance,limited joints and convenient installation.We started to use the PAP pipe in fuel gas conveyance 21 years ago.It has excellent performance in indoor gas application.Later,a unique method was designed to apply the PAP pipe in outdoor gas conveyance with the appearance of outdoor gas meter setting,which involves the addition of UPVC casing pipe as a protection technique to prevent the aging of PAP pipe.The method allows the PAP pipe to climb on the outer wall of building and get into user’s home directly after the connection with outdoor gas meter without any joints in the middle.Since 1996,the number of users has increased gradually and it achieves millions level globally today,including Europe,Asia,Oceania,South America and Africa.There were no quality and performance issues of using the PAP pipe in fuel gas conveyance indoor and outdoor in the past 20 years.In this paper,we put our effort on studying the effects of environmental temperature,sealing reliability,resistance to pipe pull-out,thermal compensation,and rat biting on PAP pipe and solve these problems.展开更多
During the tunnel construction process,unfavorable geological conditionsare often encountered.Geological disasters such as collapse,roof fall,water inrush,gas explosion,etc.occur frequently,causing different degrees o...During the tunnel construction process,unfavorable geological conditionsare often encountered.Geological disasters such as collapse,roof fall,water inrush,gas explosion,etc.occur frequently,causing different degrees of property damage and casualties to the construction of the tunnel,seriously affecting harmony during construction.The domestic emergency hedging is mainly the use of 8-10mm steel coils,but the steel is heavy and not suitable for the frequent movement of tunnels.This paper introduces the new Glass Fiber Reinforced Polymer Composite(GFRPC)escape pipeline used in Chongqing Jiuyongyi Jinyunshan Tunnel,and compares the traditional steel coil parameters to provide reference for subsequent tunnel hedging measures.展开更多
Aphysical model facility was designed, built, and setup for conducting model tests on a composite foundation in a soil ground. The model tests were carried out on a composite foundation with different combinations of ...Aphysical model facility was designed, built, and setup for conducting model tests on a composite foundation in a soil ground. The model tests were carried out on a composite foundation with different combinations of vertical reinforcement elements in the same soil ground. Via the analysis of the collected data the characteristics of the composite foundation with different reinforcing elements were obtained, including the characteristics of load-settlement curves, column stresses, stresses of the intercolumn soil, pile-soil stress ratio, and load-sharing ratios of columns and soil. Results from the model tests reveal the mechanism of a composite foundation with different reinforcing elements quantitatively. It is concluded that both a composite foundation with a combination of steel pipe pile and sand column and that with a combination of concrete pile and lime column have a higher bearing capacity than the composite foundation with only sand columns with the same conditions of soil ground and loading. A composite foundation with lime column and sand column embodies no much better performance than that with sand colunms only.展开更多
The traditional reinforced concrete structure has the problems of structural performance degradation, as well as the low shear strength, poor ductility and other seismic performance, which leads to the failure or even...The traditional reinforced concrete structure has the problems of structural performance degradation, as well as the low shear strength, poor ductility and other seismic performance, which leads to the failure or even collapse of the bridge. Key joints and Bridges with high durability requirements should adopt pier forms with superior anti-corrosion performance and seismic performance. This paper presents a composite material-concrete-steel composite pier column, which is composed of glass fiber wound steel outer pipe, steel inner pipe and concrete filled between them. The composite column is expected to have superior corrosion resistance, ductility and seismic performance. In this paper, the joint construction and design method of the composite column and foundation are introduced to provide ideas for the design and application of the composite column.展开更多
In the symplectic space composed of the original variables,displacements,and their dual variables,stresses,the symplectic solution for the composite laminates based on the Pipes-Pagano model is established in this pap...In the symplectic space composed of the original variables,displacements,and their dual variables,stresses,the symplectic solution for the composite laminates based on the Pipes-Pagano model is established in this paper.In contrast to the traditional technique using only one kind of variables,the symplectic dual variables include displacement components as well as stress components.Therefore,the compatibility conditions of displacement and stress at interfaces can be formulated simultaneously.After being introduced into the symplectic dual system,the uniform schemes,such as the separation of variables and symplectic eigenfunction expansion method,can be implemented conveniently to analyze composite laminate problems.An analytical solution for the free edge effect of composite laminates is obtained,showing the effectiveness of the symplectic dual method in analyzing composite laminates.展开更多
The vortex-induced nonlinear vibration of casing pipes in the deep water was studied considering the loads of current and combined wave-current. The vortex-induced vibration equation of a casing pipe was set up consid...The vortex-induced nonlinear vibration of casing pipes in the deep water was studied considering the loads of current and combined wave-current. The vortex-induced vibration equation of a casing pipe was set up considering the beam mode and Morison’s nonlinear fluid loads as well as the vortex-excited loads. The approach of calculating vortex-excited nonlinear vibration by Galerkin’s method was proposed. The natural vibration frequencies and modes were obtained, and the response including primary resonance induced by current and the composite resonance under combined wave-current for the 170 m long casing pipe in the 160m depth of water were investigated. The results show that the dynamics response of casing pipe obviously increases, and the complicated response behaviors of casing pipe are described under combined wave-current.展开更多
文摘The effect of additives containing rare earth elements La and Y on the structure and mechanical property of ceramic-lined composite pipe was studied in presence of centrifugation. The fracture and shearing strength of ceramic-lined composite pipe containing different additives were measured and analyzed through the fracture and shearing strength experiments. The distribution of shear stress on the interface of ceramic layer and the pipe is computed by finite element method.
基金Supported by the Natural Science Foundation of Ministry of Education of Jiangsu Province (02KJB470001).
文摘Oscillating heat pipes (OHPs) are very promising cooling devices. Their heat transfer performance is af- fected by many factors, and the form of the relationship between the performance and the factors is complex and non-linear. In this paper, the effects of charging ratio, inclination angle, and heat input and their interaction effects on heat transfer performance of a looped copper-water OHP are analyzed. First, suppose that the relationship between the response and the variables approximates a second-order model. And use the central composite design to arrange the ex- periment. Then, the method of least squares is used to estimate the parameters in the second-order model. Finally, multi- variate variance analysis is used to analyze the model. The results show that the assumption is right, that is to say, the re- lationship is well modeled by a second-order function. Among the three main effect variables, the effect of inclination angle is the most significant, but their interaction effects are not significant. In the range of the considered factors, both the optimum charging ratio and the optimum inclination angle increase as the heating water flow rate increases.
基金the National Natural Science Foundation of China(No.41121061)the National Basic Re-search Program(973)of China(Nos.2012CB026101 and 2011CB013505)+1 种基金the Western Project Program of the Chinese Academy of Sciences(No.KZCX2-XB3-19)the Open Fund of State Key Laboratory of Frozen Soil Engineering(No.SKLFSE201209)
文摘Based on the advantages of perforated ventilation characteristic of perforated ventilation pipe embankment and large porosity of blocky stone embankment, composite embankment with ventilation pipe and blocky stone is more efficient to protect the underlying permafrost. The temperature fields and cooling effect of composite embankment with air doors are simulated by examining the effects of holes＇ position drilled in the pipe, diameter in pipe and density of holes. It is shown that the underlying permafrost temperature obviously reduces by composite methods, the location of 0℃ isotherm raises significantly, especially permafrost temperature under the center and shoulder of embankment reduces more quickly, the composite embankment with holes drilled in the lower side of pipe is the most efficient, the increase of diameter has a slight influence on the 0℃ isotherm＇s raising, and the density of holes slightly influences the raising of 0℃ isotherm.
文摘<div style="text-align:justify;"> In view of the serious lack and lag of the test and evaluation technology of non-metallic composite continuous pipe, and focusing on the characteristics of the application of non-metallic composite continuous pipe in oil field, this paper discusses a series of new full-scale test and evaluation technologies for accurately evaluating the product quality and practical application performance of non-metallic composite continuous pipe, which effectively solves the major technical problem that the new products of non-metallic pipe cannot be accurately evaluated. Based on the characteristics of the application of non-metallic composite continuous pipe in oil field, a series of new full-scale test evaluation technologies which can accurately evaluate the product quality and practical application performance of non-metallic pipe are designed through a large number of tests. The test and evaluation technology can accurately evaluate the key performance of high and low pressure cycle, high and low temperature cycle, gas permeability resistance, minimum bending radius etc. It provides a scientific evaluation basis for the standardized application of non-metallic continuous pipe and a reliable quality control method for the selection of products in oil field. </div>
文摘The PE-Al-PE composite pipe is a multiplayer pipe t hat is composed of PE (polyethylene) and Aluminum. Al is inlayed the inner PE la yer and the outer PE layer. In the producing technological process of this kind of pipe the bend forming of Al belt to tube is very important. It is the bend fo rming dies that are used in the process of producing PE-Al-PE pipe that is stu died in this article. To make a elaborate division, these dies can be classified as bending dies and forming dies here. In this paper, the designation of bendin g dies and forming dies that are used in producing technological process of PE- Al-PE pipe is put forward. The process starts from a coil of Al belt, in the ac tion of pulling force, passes between several bending dies to change its shape. The first step is to change Al belt to U shape. A couple of rolling wheels can b e used to shape the Al belt. The Al belt goes between the two rolling wheels, dr ives the wheels, at the same time is formed as the shape of the rolling wheels. Considering of the factors such as spring of the bend Al belt, frictional force between Al and the die, bending force needed to bend Al belt, etc., it must be s haped gradually into U by several dies. The designation of these dies has been g iven in this paper. The next step is to forming the U shape into a circle. The U shape Al belt goes through a round that is formed with a four-roller die, and then is shaped to a circle. Because the latter procedure requires the Al circle has a laminated area to be ultrasonic welded, this die must be designed to let t he two edges of the circle belt to be piled up to a definite width. But except f or the laminated area the other of the circle should be as round as possible. So the four rollers are not the same. The calculation and designation of the rolle rs of this four-roller die has also been given. The designation of the roller w hich is supposed to leave a gap to let the two edges of the circle belt to be pi led up is to make a fine rotation of an original circle. Then calculates the cen ter of the rotated arc and defines the arc completely. The designation method of the other rollers has also been given in this paper.
文摘Polyethylene-steel Composite Pipes is widely used in conveying corrosive media occasions,but the pipe may lose effectiveness in the process of transporting hot and cold media,so the research of stress distribution and variation in polyethylene-steel composite pipes is very necessary.This article first assume that a thin adhesive layer is in between the polyethylene and steel,the adhesive layer along the axial shear stress is the major cause of the polyethylene layer and the steel pipe off sticky.Secondly,we use a method of finite element to computer simulation by ANSYS,and verify initial assumptions.Finally,based on simulation data,we analyse the adhesive layer stress distribution and the variation with different parameters to change.Through the above research,preliminarily summarize the variation and distribution of interlaminar stress,and provide technical support for future design and process improvement of polyethylenesteel pipe.
基金supported by the Science and Technology Development Fund of Macao(Grant No.0079/2019/AMJ)the National Key R&D Program of China(No.2019YFE0111400).
文摘Urban sewer pipes are a vital infrastructure in modern cities,and their defects must be detected in time to prevent potential malfunctioning.In recent years,to relieve the manual efforts by human experts,models based on deep learning have been introduced to automatically identify potential defects.However,these models are insufficient in terms of dataset complexity,model versatility and performance.Our work addresses these issues with amulti-stage defect detection architecture using a composite backbone Swin Transformer.Themodel based on this architecture is trained using a more comprehensive dataset containingmore classes of defects.By ablation studies on the modules of combined backbone Swin Transformer,multi-stage detector,test-time data augmentation and model fusion,it is revealed that they all contribute to the improvement of detection accuracy from different aspects.The model incorporating all these modules achieves the mean Average Precision(mAP)of 78.6% at an Intersection over Union(IoU)threshold of 0.5.This represents an improvement of 14.1% over the ResNet50 Faster Region-based Convolutional Neural Network(R-CNN)model and a 6.7% improvement over You Only Look Once version 6(YOLOv6)-large,the highest in the YOLO methods.In addition,for other defect detection models for sewer pipes,although direct comparison with themis infeasible due to the unavailability of their private datasets,our results are obtained from a more comprehensive dataset and have superior generalization capabilities.
基金The National Natural Science Foundation of China (No.50478090)
文摘A set of serf-developed apparatus for foundation physical model were utilized to conduct model tests of the multi-element composite foundation with a steel pipe pile and several gravel piles. Some load-bearing characteristics of the multi-element Composite foundation, including the curves of foundation settlement, stresses of piles, pile-soil stress ratio, and load-sharing ratio of piles and soil, were obtained to study its working performances in silty sand soil. The experimental results revealed that the multi-element composite foundation with steel pipe pile and gravel pile contributed more than the gravel pile composite foundation in improving the bearing capacity of the silty fine sand.
文摘Polyethylene/aluminum/polyethylene(PAP)composite pipe has the advantages of corrosion resistance,limited joints and convenient installation.We started to use the PAP pipe in fuel gas conveyance 21 years ago.It has excellent performance in indoor gas application.Later,a unique method was designed to apply the PAP pipe in outdoor gas conveyance with the appearance of outdoor gas meter setting,which involves the addition of UPVC casing pipe as a protection technique to prevent the aging of PAP pipe.The method allows the PAP pipe to climb on the outer wall of building and get into user’s home directly after the connection with outdoor gas meter without any joints in the middle.Since 1996,the number of users has increased gradually and it achieves millions level globally today,including Europe,Asia,Oceania,South America and Africa.There were no quality and performance issues of using the PAP pipe in fuel gas conveyance indoor and outdoor in the past 20 years.In this paper,we put our effort on studying the effects of environmental temperature,sealing reliability,resistance to pipe pull-out,thermal compensation,and rat biting on PAP pipe and solve these problems.
文摘During the tunnel construction process,unfavorable geological conditionsare often encountered.Geological disasters such as collapse,roof fall,water inrush,gas explosion,etc.occur frequently,causing different degrees of property damage and casualties to the construction of the tunnel,seriously affecting harmony during construction.The domestic emergency hedging is mainly the use of 8-10mm steel coils,but the steel is heavy and not suitable for the frequent movement of tunnels.This paper introduces the new Glass Fiber Reinforced Polymer Composite(GFRPC)escape pipeline used in Chongqing Jiuyongyi Jinyunshan Tunnel,and compares the traditional steel coil parameters to provide reference for subsequent tunnel hedging measures.
基金Project (No.50478090) supported by the National Natural Science Foundation of China
文摘Aphysical model facility was designed, built, and setup for conducting model tests on a composite foundation in a soil ground. The model tests were carried out on a composite foundation with different combinations of vertical reinforcement elements in the same soil ground. Via the analysis of the collected data the characteristics of the composite foundation with different reinforcing elements were obtained, including the characteristics of load-settlement curves, column stresses, stresses of the intercolumn soil, pile-soil stress ratio, and load-sharing ratios of columns and soil. Results from the model tests reveal the mechanism of a composite foundation with different reinforcing elements quantitatively. It is concluded that both a composite foundation with a combination of steel pipe pile and sand column and that with a combination of concrete pile and lime column have a higher bearing capacity than the composite foundation with only sand columns with the same conditions of soil ground and loading. A composite foundation with lime column and sand column embodies no much better performance than that with sand colunms only.
文摘The traditional reinforced concrete structure has the problems of structural performance degradation, as well as the low shear strength, poor ductility and other seismic performance, which leads to the failure or even collapse of the bridge. Key joints and Bridges with high durability requirements should adopt pier forms with superior anti-corrosion performance and seismic performance. This paper presents a composite material-concrete-steel composite pier column, which is composed of glass fiber wound steel outer pipe, steel inner pipe and concrete filled between them. The composite column is expected to have superior corrosion resistance, ductility and seismic performance. In this paper, the joint construction and design method of the composite column and foundation are introduced to provide ideas for the design and application of the composite column.
基金supported by the National Basic Research Program of China (No. 2010CB832704)the National Natural Science Foundation of China (No. 10772039)
文摘In the symplectic space composed of the original variables,displacements,and their dual variables,stresses,the symplectic solution for the composite laminates based on the Pipes-Pagano model is established in this paper.In contrast to the traditional technique using only one kind of variables,the symplectic dual variables include displacement components as well as stress components.Therefore,the compatibility conditions of displacement and stress at interfaces can be formulated simultaneously.After being introduced into the symplectic dual system,the uniform schemes,such as the separation of variables and symplectic eigenfunction expansion method,can be implemented conveniently to analyze composite laminate problems.An analytical solution for the free edge effect of composite laminates is obtained,showing the effectiveness of the symplectic dual method in analyzing composite laminates.
基金Project supported by the National Natural Science Foundation of China (No.50279026) andthe National985Engineering Project in China
文摘The vortex-induced nonlinear vibration of casing pipes in the deep water was studied considering the loads of current and combined wave-current. The vortex-induced vibration equation of a casing pipe was set up considering the beam mode and Morison’s nonlinear fluid loads as well as the vortex-excited loads. The approach of calculating vortex-excited nonlinear vibration by Galerkin’s method was proposed. The natural vibration frequencies and modes were obtained, and the response including primary resonance induced by current and the composite resonance under combined wave-current for the 170 m long casing pipe in the 160m depth of water were investigated. The results show that the dynamics response of casing pipe obviously increases, and the complicated response behaviors of casing pipe are described under combined wave-current.
