Cellular thin-shell structures are widely applied in ultralightweight designs due to their high bearing capacity and strength-to-weight ratio.In this paper,a full-scale isogeometric topology optimization(ITO)method ba...Cellular thin-shell structures are widely applied in ultralightweight designs due to their high bearing capacity and strength-to-weight ratio.In this paper,a full-scale isogeometric topology optimization(ITO)method based on Kirchhoff-Love shells for designing cellular tshin-shell structures with excellent damage tolerance ability is proposed.This method utilizes high-order continuous nonuniform rational B-splines(NURBS)as basis functions for Kirchhoff-Love shell elements.The geometric and analysis models of thin shells are unified by isogeometric analysis(IGA)to avoid geometric approximation error and improve computational accuracy.The topological configurations of thin-shell structures are described by constructing the effective density field on the controlmesh.Local volume constraints are imposed in the proximity of each control point to obtain bone-like cellular structures.To facilitate numerical implementation,the p-norm function is used to aggregate local volume constraints into an equivalent global constraint.Several numerical examples are provided to demonstrate the effectiveness of the proposed method.After simulation and comparative analysis,the results indicate that the cellular thin-shell structures optimized by the proposed method exhibit great load-carrying behavior and high damage robustness.展开更多
This study is a brief attempt to uncover the secret of love.From the extremely rich literature on the subject,it relies on only four classic thinkers and writers(Plato,Shakespeare,Attila József,Marx),among whom M...This study is a brief attempt to uncover the secret of love.From the extremely rich literature on the subject,it relies on only four classic thinkers and writers(Plato,Shakespeare,Attila József,Marx),among whom Marx’s relevant statement is less known even among love researchers.Furthermore,it intends to draw attention to some notable Hungarian philosophers and poets.The ultimate message of the examination is that,although love is the subjective,intimate sphere of a person,it hopefully becomes clear how lovers can create human and communal relationships with each other and with their narrower and broader environment.展开更多
At my school,we made donations to children in the flooded areas last week.All the teachers and students volunteered,so did I.Besides books,I donated schoolbags,clothes,toys and so on.I am willing giving①away these th...At my school,we made donations to children in the flooded areas last week.All the teachers and students volunteered,so did I.Besides books,I donated schoolbags,clothes,toys and so on.I am willing giving①away these things,because I feel it's my duty to help those in trouble.展开更多
This paper scrutinizes the differences in the conceptualization of love between Korean and American women.Grounded in an analysis of literary figures,Brett and Kim Ji-young,the study unravels the intricate interplay o...This paper scrutinizes the differences in the conceptualization of love between Korean and American women.Grounded in an analysis of literary figures,Brett and Kim Ji-young,the study unravels the intricate interplay of cultural,historical,and societal forces shaping these perspectives.The contrasting landscapes of the United States,driven by ideals of freedom and individualism,and Korea,entrenched in Confucian values and collectivism,serve as crucibles for forming women’s roles,self-perception,and societal expectations.The examination extends to communication styles,illuminating the directness of American expression versus Korea’s reliance on formalism.Through this exploration,the paper illustrates the profound impact of cultural contexts on the intricate tapestry of love,offering a nuanced understanding of divergent viewpoints within a global context.展开更多
Based upon Ihe differntial equations and their related boundary conditions givenin the prerious papert[1], this poper finds the analytical solution of non-Kirchhoff-Lovetheory for elastic circular plate with fixed bou...Based upon Ihe differntial equations and their related boundary conditions givenin the prerious papert[1], this poper finds the analytical solution of non-Kirchhoff-Lovetheory for elastic circular plate with fixed boundary conditions under uniform surfaceloading. However, for the sake of Saving conrputational work. the first orderapproximation theory can be further simplified in more rational bases.展开更多
Based on the approximation theory adopting non-Kirchhoff-Love assumption forthree dimensional elaslic plates with arbitrary shapes[1][2], the author derives afunctional of generalized variation for three dimensional e...Based on the approximation theory adopting non-Kirchhoff-Love assumption forthree dimensional elaslic plates with arbitrary shapes[1][2], the author derives afunctional of generalized variation for three dimensional elastic circular plates, therebyobtains a set of differtial equations and the relate boundary conditions to establish afirst order approximation theory for elastic circular plate with fixed boundary andunder uniform loading on one of its surface. The analytical solution of this problemwill present in another paper.展开更多
ased upon the differential equations and their related boundary conditions givenin the previous papers[1, 2], using a global interpolation method, this paper presents anumerical solution to the axisymmetric bending pr...ased upon the differential equations and their related boundary conditions givenin the previous papers[1, 2], using a global interpolation method, this paper presents anumerical solution to the axisymmetric bending problem of non-Kirchhoff-Love theoryfor circular plate with fixed boundary under uniform surface loading. All the numericalresults obtained in this paper are compared with that of Kirchhoff-Love classicaltheory[3] and E. Reissner's modified theory[4]展开更多
Research on the propagation of elastic waves in piezoelectric nanostructures is very limited. The frequency dispersion of Love waves in layered piezoelectric nanostructures has not yet been reported when surface effec...Research on the propagation of elastic waves in piezoelectric nanostructures is very limited. The frequency dispersion of Love waves in layered piezoelectric nanostructures has not yet been reported when surface effects are taken into account. Based on the surface elasticity theory, the propagation of Love waves with surface effects in a structure consisting of a nanosized piezoelectric film and a semi-infinite elastic substrate is investigated focusing on the frequency dispersion curves of different modes. The results show that under the electrically-open conditions, surface effects give rise to the dependence of Love wave dispersion on the film thickness when the thickness of the piezoelectric film reduces to nanometers. For a given wave frequency, phase velocity of Love waves in all dispersion modes exhibit obvious toward shift as the film thickness decreases or the surface parameters increase. Moreover, there may exist a cut-off frequency in the first mode dispersion below which Love waves will be evanescent in the structure due to surface effects. The cut-off frequency depends on the film thickness, the surface parameters and the bulk material properties.展开更多
The scattering of Love waves by an interface crack between apiezoelectric layers and an elas- tic substrate is investigated byusing the integral transform and singular integral equationtechniques. The dy- namic stress...The scattering of Love waves by an interface crack between apiezoelectric layers and an elas- tic substrate is investigated byusing the integral transform and singular integral equationtechniques. The dy- namic stress intensity factors of the left andthe right crack tips are determined. It is found from numericalcalculation that the dynamic response of the system dependssignificantly on the crack configuration, the ma- terial combinationand the propagating direction of the incident wave. It is expectedthat specifying an appro- priate material combination may retard thegrowth of the crack for a certain crack configuration.展开更多
Poetry is one of the most important literary forms in English literature.Love is an eternal theme among poems of different periods.Influenced by different social backgrounds,the poets express their strong feelings fro...Poetry is one of the most important literary forms in English literature.Love is an eternal theme among poems of different periods.Influenced by different social backgrounds,the poets express their strong feelings from different perspectives.By employing the methods of literature review and comparative study,this paper attempts to explore their images,themes and other literary characteristics,which contributes to better understanding about the love theme.展开更多
The Lovely Bones written by Alice Sebold is about a 14-year-old girl Susie who,as a ghost,tells her story as well as her family's after her death.Tiffs paper focuses on the characteristics of the first-person retr...The Lovely Bones written by Alice Sebold is about a 14-year-old girl Susie who,as a ghost,tells her story as well as her family's after her death.Tiffs paper focuses on the characteristics of the first-person retrospective narrative in The Lovely Bones.Firstly,this paper introduces the story,the double focalizations of the first--person retrospective narrative and the purpose of the paper.It then discusses the three functions of the first-person retrospective narrative:enhancing authenticity,intensifying intimacy and contributing to the love theme of the story.Besides,the thesis points out the limitation of the first-person retrospective narrative:monotonous.Therefore,a shift of the narrative perspective is put forwards as the solution to the problem.展开更多
John Donne,being famous for his use of metaphysical metaphors,is one of the most successful poets of the 17th century English.His metaphysical poem“A Valediction:Forbidding Mourning”plays a significant role during t...John Donne,being famous for his use of metaphysical metaphors,is one of the most successful poets of the 17th century English.His metaphysical poem“A Valediction:Forbidding Mourning”plays a significant role during the Renaissance.In his poems,the compass is compared to lovers,which becomes the classic love metaphor.This essay aims to analyze the discrepancy between the death at the beginning and the love’s constancylater,and how John Donne illustrates two groups of contrast:spiritual love and physical love,temporal love and eternal love.展开更多
A detailed investigation is presented for Love waves （LWs） with thick viscoelastic guiding layers. A theoretical calculation and an experiment are carried out for LW devices incorporating an SU-8 guiding layer, an S...A detailed investigation is presented for Love waves （LWs） with thick viscoelastic guiding layers. A theoretical calculation and an experiment are carried out for LW devices incorporating an SU-8 guiding layer, an ST-90° X quartz substrate and two 28-μm periodic interdigital transducers. Both the calculated and the measured results show an increase in propagation velocity when h / λ〉0.05. The measured insertion loss of LWs is consistent with the calculated propagation loss. The insertion loss of bulk waves is also measured and is compared with that of LWs.展开更多
Based on the general theory of elastic plates which abandons Kirchhoff-Loveassunption in the classical theory. this paper establishes a first order approximationtheory of elastic circular plates with non-Kirchhoff-Lov...Based on the general theory of elastic plates which abandons Kirchhoff-Loveassunption in the classical theory. this paper establishes a first order approximationtheory of elastic circular plates with non-Kirchhoff-Love assumption, and presents ananalytic solution to the axisymmetric problem of elastic circular plates with clampedboundary under uniformly distributed load. By comparing with the classical solution ofthe thin circular plates, it is verified that the new solution is closer to the experimentresults than the classical solution. By virtue of the new theory. the influence of thediameter-to=thickness ratio upon the precision of the classical theory is examined.展开更多
基金supported by the National Key R&D Program of China(Grant Number 2020YFB1708300)China National Postdoctoral Program for Innovative Talents(Grant Number BX20220124)+1 种基金China Postdoctoral Science Foundation(Grant Number 2022M710055)the New Cornerstone Science Foundation through the XPLORER PRIZE,the Knowledge Innovation Program of Wuhan-Shuguang,the Young Top-Notch Talent Cultivation Program of Hubei Province and the Taihu Lake Innovation Fund for Future Technology(Grant Number HUST:2023-B-7).
文摘Cellular thin-shell structures are widely applied in ultralightweight designs due to their high bearing capacity and strength-to-weight ratio.In this paper,a full-scale isogeometric topology optimization(ITO)method based on Kirchhoff-Love shells for designing cellular tshin-shell structures with excellent damage tolerance ability is proposed.This method utilizes high-order continuous nonuniform rational B-splines(NURBS)as basis functions for Kirchhoff-Love shell elements.The geometric and analysis models of thin shells are unified by isogeometric analysis(IGA)to avoid geometric approximation error and improve computational accuracy.The topological configurations of thin-shell structures are described by constructing the effective density field on the controlmesh.Local volume constraints are imposed in the proximity of each control point to obtain bone-like cellular structures.To facilitate numerical implementation,the p-norm function is used to aggregate local volume constraints into an equivalent global constraint.Several numerical examples are provided to demonstrate the effectiveness of the proposed method.After simulation and comparative analysis,the results indicate that the cellular thin-shell structures optimized by the proposed method exhibit great load-carrying behavior and high damage robustness.
文摘This study is a brief attempt to uncover the secret of love.From the extremely rich literature on the subject,it relies on only four classic thinkers and writers(Plato,Shakespeare,Attila József,Marx),among whom Marx’s relevant statement is less known even among love researchers.Furthermore,it intends to draw attention to some notable Hungarian philosophers and poets.The ultimate message of the examination is that,although love is the subjective,intimate sphere of a person,it hopefully becomes clear how lovers can create human and communal relationships with each other and with their narrower and broader environment.
文摘At my school,we made donations to children in the flooded areas last week.All the teachers and students volunteered,so did I.Besides books,I donated schoolbags,clothes,toys and so on.I am willing giving①away these things,because I feel it's my duty to help those in trouble.
文摘This paper scrutinizes the differences in the conceptualization of love between Korean and American women.Grounded in an analysis of literary figures,Brett and Kim Ji-young,the study unravels the intricate interplay of cultural,historical,and societal forces shaping these perspectives.The contrasting landscapes of the United States,driven by ideals of freedom and individualism,and Korea,entrenched in Confucian values and collectivism,serve as crucibles for forming women’s roles,self-perception,and societal expectations.The examination extends to communication styles,illuminating the directness of American expression versus Korea’s reliance on formalism.Through this exploration,the paper illustrates the profound impact of cultural contexts on the intricate tapestry of love,offering a nuanced understanding of divergent viewpoints within a global context.
文摘Based upon Ihe differntial equations and their related boundary conditions givenin the prerious papert[1], this poper finds the analytical solution of non-Kirchhoff-Lovetheory for elastic circular plate with fixed boundary conditions under uniform surfaceloading. However, for the sake of Saving conrputational work. the first orderapproximation theory can be further simplified in more rational bases.
文摘Based on the approximation theory adopting non-Kirchhoff-Love assumption forthree dimensional elaslic plates with arbitrary shapes[1][2], the author derives afunctional of generalized variation for three dimensional elastic circular plates, therebyobtains a set of differtial equations and the relate boundary conditions to establish afirst order approximation theory for elastic circular plate with fixed boundary andunder uniform loading on one of its surface. The analytical solution of this problemwill present in another paper.
文摘ased upon the differential equations and their related boundary conditions givenin the previous papers[1, 2], using a global interpolation method, this paper presents anumerical solution to the axisymmetric bending problem of non-Kirchhoff-Love theoryfor circular plate with fixed boundary under uniform surface loading. All the numericalresults obtained in this paper are compared with that of Kirchhoff-Love classicaltheory[3] and E. Reissner's modified theory[4]
基金Supported by National Natural Science Foundation of China(Grant No.11372261)Excellent Young Scientists Supporting Project of Science and Technology Department of Sichuan Province,China(Grant No.2013JQ0030)+4 种基金Supporting Project of Department of Education of Sichuan Province,China(Grant No.2014zd3132)Opening Project of Key Laboratory of Testing Technology for Manufacturing ProcessSouthwest University of Science and Technology-Ministry of Education,China(Grant No.12zxzk02)Fund of Doctoral Research of Southwest University of Science and Technology,China(Grant No.12zx7106)Postgraduate Innovation Fund of Southwest University of Science and Technology,China(Grant No.15ycx128)
文摘Research on the propagation of elastic waves in piezoelectric nanostructures is very limited. The frequency dispersion of Love waves in layered piezoelectric nanostructures has not yet been reported when surface effects are taken into account. Based on the surface elasticity theory, the propagation of Love waves with surface effects in a structure consisting of a nanosized piezoelectric film and a semi-infinite elastic substrate is investigated focusing on the frequency dispersion curves of different modes. The results show that under the electrically-open conditions, surface effects give rise to the dependence of Love wave dispersion on the film thickness when the thickness of the piezoelectric film reduces to nanometers. For a given wave frequency, phase velocity of Love waves in all dispersion modes exhibit obvious toward shift as the film thickness decreases or the surface parameters increase. Moreover, there may exist a cut-off frequency in the first mode dispersion below which Love waves will be evanescent in the structure due to surface effects. The cut-off frequency depends on the film thickness, the surface parameters and the bulk material properties.
基金the National Natural Science Foundation of China (No.19891180)the Fundamental Research Foundation of Tsinghua University (JZ 2000.007)the Fund of the Education Ministry of China.
文摘The scattering of Love waves by an interface crack between apiezoelectric layers and an elas- tic substrate is investigated byusing the integral transform and singular integral equationtechniques. The dy- namic stress intensity factors of the left andthe right crack tips are determined. It is found from numericalcalculation that the dynamic response of the system dependssignificantly on the crack configuration, the ma- terial combinationand the propagating direction of the incident wave. It is expectedthat specifying an appro- priate material combination may retard thegrowth of the crack for a certain crack configuration.
文摘Poetry is one of the most important literary forms in English literature.Love is an eternal theme among poems of different periods.Influenced by different social backgrounds,the poets express their strong feelings from different perspectives.By employing the methods of literature review and comparative study,this paper attempts to explore their images,themes and other literary characteristics,which contributes to better understanding about the love theme.
文摘The Lovely Bones written by Alice Sebold is about a 14-year-old girl Susie who,as a ghost,tells her story as well as her family's after her death.Tiffs paper focuses on the characteristics of the first-person retrospective narrative in The Lovely Bones.Firstly,this paper introduces the story,the double focalizations of the first--person retrospective narrative and the purpose of the paper.It then discusses the three functions of the first-person retrospective narrative:enhancing authenticity,intensifying intimacy and contributing to the love theme of the story.Besides,the thesis points out the limitation of the first-person retrospective narrative:monotonous.Therefore,a shift of the narrative perspective is put forwards as the solution to the problem.
文摘John Donne,being famous for his use of metaphysical metaphors,is one of the most successful poets of the 17th century English.His metaphysical poem“A Valediction:Forbidding Mourning”plays a significant role during the Renaissance.In his poems,the compass is compared to lovers,which becomes the classic love metaphor.This essay aims to analyze the discrepancy between the death at the beginning and the love’s constancylater,and how John Donne illustrates two groups of contrast:spiritual love and physical love,temporal love and eternal love.
基金Supported by the National Natural Science Foundation of China under Grant No 11104314
文摘A detailed investigation is presented for Love waves （LWs） with thick viscoelastic guiding layers. A theoretical calculation and an experiment are carried out for LW devices incorporating an SU-8 guiding layer, an ST-90° X quartz substrate and two 28-μm periodic interdigital transducers. Both the calculated and the measured results show an increase in propagation velocity when h / λ〉0.05. The measured insertion loss of LWs is consistent with the calculated propagation loss. The insertion loss of bulk waves is also measured and is compared with that of LWs.
文摘Based on the general theory of elastic plates which abandons Kirchhoff-Loveassunption in the classical theory. this paper establishes a first order approximationtheory of elastic circular plates with non-Kirchhoff-Love assumption, and presents ananalytic solution to the axisymmetric problem of elastic circular plates with clampedboundary under uniformly distributed load. By comparing with the classical solution ofthe thin circular plates, it is verified that the new solution is closer to the experimentresults than the classical solution. By virtue of the new theory. the influence of thediameter-to=thickness ratio upon the precision of the classical theory is examined.
