Transient response of doubly-curved bio-inspired composite shells resting on viscoelastic foundation subject to blast load using improved first-order shear theory and isogeometric approach

Investigating natural-inspired applications is a perennially appealing subject for scientists. The current increase in the speed of natural-origin structure growth may be linked to their superior mechanical properties and environmental resilience. Biological composite structures with helicoidal schemes and designs have remarkable capacities to absorb impact energy and withstand damage. However, there is a dearth of extensive study on the influence of fiber redirection and reorientation inside the matrix of a helicoid structure on its mechanical performance and reactivity. The present study aimed to explore the static and transient responses of a bio-inspired helicoid laminated composite(B-iHLC) shell under the influence of an explosive load using an isomorphic method. The structural integrity of the shell is maintained by a viscoelastic basis known as the Pasternak foundation, which encompasses two coefficients of stiffness and one coefficient of damping. The equilibrium equations governing shell dynamics are obtained by using Hamilton's principle and including the modified first-order shear theory,therefore obviating the need to employ a shear correction factor. The paper's model and approach are validated by doing numerical comparisons with respected publications. The findings of this study may be used in the construction of military and civilian infrastructure in situations when the structure is subjected to severe stresses that might potentially result in catastrophic collapse. The findings of this paper serve as the foundation for several other issues, including geometric optimization and the dynamic response of similar mechanical structures.

Static Analysis of Anisotropic Doubly-Curved Shell Subjected to Concentrated Loads Employing Higher Order Layer-Wise Theories

In the presentmanuscript,a Layer-Wise(LW)generalizedmodel is proposed for the linear static analysis of doublycurved shells constrained with general boundary conditions under the influence of concentrated and surface loads.The unknown field variable is modelled employing polynomials of various orders,each of them defined within each layer of the structure.As a particular case of the LW model,an Equivalent Single Layer(ESL)formulation is derived too.Different approaches are outlined for the assessment of external forces,as well as for non-conventional constraints.The doubly-curved shell is composed by superimposed generally anisotropic laminae,each of them characterized by an arbitrary orientation.The fundamental governing equations are derived starting from an orthogonal set of principal coordinates.Furthermore,generalized blending functions account for the distortion of the physical domain.The implementation of the fundamental governing equations is performed bymeans of the Generalized Differential Quadrature(GDQ)method,whereas the numerical integrations are computed employing theGeneralized IntegralQuadrature(GIQ)method.In the post-processing phase,an effective procedure is adopted for the reconstruction of stress and strain through-the-thickness distributions based on the exact fulfillment of three-dimensional equilibrium equations.A series of systematic investigations are performed in which the static response of structures with various curvatures and lamination schemes,calculated by the present methodology,have been successfully compared to those ones obtained fromrefined finite element three-dimensional simulations.Even though the present LW approach accounts for a two-dimensional assessment of the structural problem,it is capable of well predicting the three-dimensional response of structures with different characteristics,taking into account a reduced computational cost and pretending to be a valid alternative to widespread numerical implementations.

A Study on Translation of Chinese Culture-loaded Words from the Per-spective of Relevance Theory

The essay tends to analyze the translation of Chinese Culture-loaded words from the perspective of Relevance Theory.The theory gains its prominence by studying the translation process and transcending the conflicts between literal and free translation. It incorporates recent work in cognitive linguistics, with ostensive-inference as its key model. Under the influence of Relevance theory, the translation of culture-loaded words is reader-oriented. Translators are obliged to help target readers to establish new assumptions to achieve equivalent response.

Load Reduction Test Method of Similarity Theory and BP Neural Networks of Large Cranes

Static load tests are an important means of supervising and detecting a crane＇s lift capacity. Due to space restrictions, however, there are difficulties and potential danger when testing large bridge cranes. To solve the loading problems of large-tonnage cranes during testing, an equivalency test is proposed based on the similarity theory and BP neural networks. The maximum stress and displacement of a large bridge crane is tested in small loads, combined with the training neural network of a similar structure crane through stress and displacement data which is collected by a physics simulation progressively loaded to a static load test load within the material scope of work. The maximum stress and displacement of a crane under a static load test load can be predicted through the relationship of stress, displacement, and load. By measuring the stress and displacement of small tonnage weights, the stress and displacement of large loads can be predicted, such as the maximum load capacity, which is 1.25 times the rated capacity. Experimental study shows that the load reduction test method can reflect the lift capacity of large bridge cranes. The load shedding predictive analysis for Sanxia 1200 t bridge crane test data indicates that when the load is 1.25 times the rated lifting capacity, the predicted displacement and actual displacement error is zero. The method solves the problem that lifting capacities are difficult to obtain and testing accidents are easily possible when 1.25 times related weight loads are tested for large tonnage cranes.

Simplified nonlinear theory of the dielectric loaded rectangular Cerenkov maser

To rapidly and accurately investigate the performance of the dielectric loaded rectangular Cerenkov maser, a simplified nonlinear theory is proposed, in which the variations of wave amplitude and wave phase are determined by two coupled first-order differential equations. Through combining with the relativistic equation of motion and adopting the forward wave assumption, the evolutions of the forward wave power, the power growth rate, the axial wave number, the accumulated phase offset, and the information of the particle movement can be obtained in a single-pass calculation. For an illustrative example, this method is used to study the influences of the beam current, the gap distance between the beam and the dielectric surface, and the momentum spread on the forward wave. The variations of the saturated power and the saturation length with the working frequency for the beams with different momentum spreads have also been studied. The result shows that the beam wave interaction is very sensitive to the electron beam state. To further verify this simplified theory, a comparison with the result produced from a rigorous method is also provided, we find that the evolution curves of the forward wave power predicted by the two methods exhibit excellent agreement. In practical applications, the developed theory can be used for the design and analysis of the rectangular Cerenkov maser.

Nonlinear vibration of embedded single-walled carbon nanotube with geometrical imperfection under harmonic load based on nonlocal Timoshenko beam theory

Based on the nonlocal continuum theory, the nonlinear vibration of an embedded single-walled carbon nanotube （SWCNT） subjected to a harmonic load is in- vestigated. In the present study, the SWCNT is assumed to be a curved beam, which is unlike previous similar work. Firstly, the governing equations of motion are derived by the Hamilton principle, meanwhile, the Galerkin approach is carried out to convert the nonlinear integral-differential equation into a second-order nonlinear ordinary differ- ential equation. Then, the precise integration method based on the local linearzation is appropriately designed for solving the above dynamic equations. Besides, the numerical example is presented, the effects of the nonlocal parameters, the elastic medium constants, the waviness ratios, and the material lengths on the dynamic response are analyzed. The results show that the above mentioned effects have influences on the dynamic behavior of the SWCNT.

On the Advantages of the Theories of Plasticity with Singular Loading Surface

This paper analyzes the peculiarities of plastic flow of metals for the case of non-proportional loading when the loading path consists of two portions—uniaxial tension and subsequent infinitesimal pure shear (torsion). The issue is discussed from the point of view of the hardening rules governing the kinetics of loading surface. Three cases are considered, flow plasticity theory with isotropic and kinematic hardening rule, as well as the synthetic theory of plastic deformation. As a result, the synthetic theory leads to the results that correlate with experiments, whereas the former two theories associated with smooth loading surfaces give a principal discrepancy with experimental data.

A new calculation method for axial load capacity of separated concrete-filled steel tubes based on limit equilibrium theory

A new calculation method for axial load capacity of separated concrete-filled steel tubes based on limit equilibrium theory was proposed,which took into account the decrease of confinement effect by steel tube and the non-uniform distribution of ultimate stress in cored concrete.The accuracy of the analytical result is validated through running the numerical result by finite element method (FEM) and experimental data as well.The influences of the key parameters on the load capacity of the concrete-filled steel tube (CFST) was studied,including the separation ratio,concrete compressive strength,and steel strength.The results indicate that the load capacity of the tube increases with concrete strength and steel strength under the separation ratio less than 4%,while decreases with a higher separation ratio improved.

A Study on the Translation of Culture Loaded Words From the Perspective of Skopos Theory

“A word is the best evidence of the reality of culture,in the sense of a historically transmitted system of conceptions and attitudes”.University website is an important window of foreign publicity while its English version is an important window for foreign students in particular.Culture loaded words,with their unique foreign flavor,are the miniature of colorful culture.Therefore,the translation of culture loaded words on university websites plays an important role in foreign publicity,as it will reflect the image of different university and indirectly affect the foreign publicity of China.This study selects from the websites of North China Electric Power University(NCEPU)two representative news and analyzes the translation of culture loaded words on university websites from the perspective of Skopos Theory.Finally,the author proposes three methods in translating these words—transliteration,literal translation,and free translation,which are suggestive for the translation of culture loaded words on the university websites.

Application of the Load/Unload Response Ratio Theory to Predictions of Moderate Earthquakes (7.0>M≥6.0)

The variation in load/unload response ratio before some moderate earthquakes is analyzed based on the theory of the load/unload response ratio.The results show that the load-unload response ratio increases noticeably before moderate earthquakes,and there are three kinds of patterns in which the load/unload response ratio varies and the duration of noticeable increase in load/unload response ratio ranges from half a year to two years.

Static Analysis of Doubly-Curved Shell Structures of Smart Materials and Arbitrary Shape Subjected to General Loads Employing Higher Order Theories and Generalized Differential Quadrature Method

The article proposes an Equivalent Single Layer(ESL)formulation for the linear static analysis of arbitrarily-shaped shell structures subjected to general surface loads and boundary conditions.A parametrization of the physical domain is provided by employing a set of curvilinear principal coordinates.The generalized blendingmethodology accounts for a distortion of the structure so that disparate geometries can be considered.Each layer of the stacking sequence has an arbitrary orientation and is modelled as a generally anisotropic continuum.In addition,re-entrant auxetic three-dimensional honeycomb cells with soft-core behaviour are considered in the model.The unknown variables are described employing a generalized displacement field and pre-determined through-the-thickness functions assessed in a unified formulation.Then,a weak assessment of the structural problem accounts for shape functions defined with an isogeometric approach starting fromthe computational grid.Ageneralizedmethodology has been proposed to define two-dimensional distributions of static surface loads.In the same way,boundary conditions with three-dimensional features are implemented along the shell edges employing linear springs.The fundamental relations are obtained from the stationary configuration of the total potential energy,and they are numerically tackled by employing the Generalized Differential Quadrature(GDQ)method,accounting for nonuniform computational grids.In the post-processing stage,an equilibrium-based recovery procedure allows the determination of the three-dimensional dispersion of the kinematic and static quantities.Some case studies have been presented,and a successful benchmark of different structural responses has been performed with respect to various refined theories.

THE ELASTO-PLASTIC STRAIN ANALYSIS OF NOTCHED PLATE UNDER CYCLIC LOADING—AN APPLICATION OF PLASTIC ANISOTROPIC HARDENING THEORY

In order to predict the life of engineering structures, it is necessary to investigate the strain distribution in notched members. In gineral, the Uauschinger Effect of materials under cyclic loading is not negligible, and so the anisolropic hardening model has been suggested. From the comparison between the calculated and experimental results in this paper, we can see that even the linear kinematic hardening model is quite suitable for strain analysis under cyclic loading.

Reliability analysis of torpedo loading based on fractional-order optimization model

A fractional-order cumulative optimization GM(1,2)model based on grey theory is proposed to study the relationship between torpedo loading and working reliabilities.In this model,the average relative error function related to order and background value is established.Taking the average relative error function as the objective function,the optimal value of the two parameters is obtained through the optimization method,and the minimum value of the average relative error is determined.The calculation example shows that this method can greatly improve the accuracy of the model and more accurately reflect the relationship between torpedo loading and working reliabilities compared with the traditional GM(1,2)model.

Translation of Culture-Loaded Words in Tales of Hulan River from the Perspective of Functional Equivalence Theory

This research analyzes the culture-loaded words in English version of Tales of Hulan River bases on functional equivalence theory.The major point is what strategies Howard Goldblatt uses to achieve the equivalences in semantic message,stylistic message,cultural message and response of readers,and the reasons why he uses them.This thesis contains four chapters,starting with the background,significances and the organization of the research.Chapter two introduces Tales of Hulan River as well as Xiao Hong and Howard Goldblatt,as well as the functional equivalence theory.To analyze the translation strategies of Goldblatt,chapter three divided the culture-loaded words into three categories,which is dialect,custom and proverb respectively,in this translation work of Tales of Hulan River from the perspective of functional equivalence theory.Last one is conclusion,summarizing the whole research.This paper highlights the translating of this novel into different languages and the spreading of Chinese culture.

Improved Control in Single Phase Inverter Grid-Tied PV System Using Modified PQ Theory

Grid-connected reactive-load compensation and harmonic control are becoming a central topic as photovoltaic(PV)grid-connected systems diversified.This research aims to produce a high-performance inverter with a fast dynamic response for accurate reference tracking and a low total har-monic distortion(THD)even under nonlinear load applications by improving its control scheme.The proposed system is expected to operate in both stand-alone mode and grid-connected mode.In stand-alone mode,the proposed controller supplies power to critical loads,alternatively during grid-connected mode provide excess energy to the utility.A modified variable step incremental conductance(VS-InCond)algorithm is designed to extract maximum power from PV.Whereas the proposed inverter controller is achieved by using a modified PQ theory with double-band hysteresis current controller(PQ-DBHCC)to produce a reference current based on a decomposition of a single-phase load current.The nonlinear rectifier loads often create significant distortion in the output voltage of single-phase inverters,due to excessive current harmonics in the grid.Therefore,the proposed method generates a close-loop reference current for the switching scheme,hence,minimizing the inverter voltage distortion caused by the excessive grid current harmonics.The simulation findings suggest the proposed control technique can effectively yield more than 97%of power conversion efficiency while suppressing the grid current THD by less than 2%and maintaining the unity power factor at the grid side.The efficacy of the proposed controller is simulated using MATLAB/Simulink.

认知负荷理论视域下教材插图编配研究

认知负荷理论是一种适合解释教材插图学习的理论,它认为学习者的学习活动主要在容量有限的工作记忆中进行,工作记忆有两条信息加工通道,分别负责处理文字内容和图片内容。有待工作记忆处理的文字内容和图片内容要彼此对应,编配方式应有利于学习者整合图文信息,且不宜让学习者的工作记忆负荷过重。在现行教材的代表性样本中,教材编配的大部分插图与文字内容相对应,教材主要采用嵌入、邻近、内容关联词、符号标志关联词等技术帮助学生建立插图与相应文字内容之间的联系,但插图与文字的有效关联技术运用得较少,教材插图的编配缺乏明确的规范。为规范教材插图的编配,应将“对应”作为插图选配的原则,适当提升嵌入技术的使用比例,充分且到位地运用图文关联技术,开展图文关联技术组合效果的研究,加强不同学科教材编写者在插图编配上的相互借鉴。

基于多维气象信息时空融合和MPA-VMD的短期电力负荷组合预测模型

为提高电力负荷预测精度,需考虑区域内不同地区多维气象信息对电力负荷影响的差异性。在空间维度上,提出多维气象信息时空融合的方法,利用Copula理论将多座气象站的风速、降雨量、温度、日照强度等气象信息与电力负荷进行非线性耦合分析并实现时空融合。在时间维度上,采用海洋捕食者算法(MPA)实现变分模态分解(VMD)核心参数的自动寻优,并采用加权排列熵构造MPA-VMD适应度函数,实现负荷序列的自适应分解。通过将时间维度各分量与空间维度各气象信息进行融合构造长短期记忆(LSTM)网络模型与海洋捕食者算法-最小二乘支持向量机(MPA-LSSVM)模型的输入集,得到各分量预测结果,根据评价指标选择各分量对应的预测模型,重构得到整体预测结果。算例分析结果表明,所提预测模型优于传统预测模型,有效提高了电力负荷预测精度。

计及不确定性的风光抽蓄发电系统容量优化

风光等新能源的大规模利用是实现双碳目标的重要途径,其不确定性影响电力系统稳定运行和对新能源的消纳能力。对此,本文提出了一种计及不确定性的风光抽蓄联合发电系统容量优化配置方法。首先,采用不同的随机分布函数来描述风电、光伏发电的出力特性和负荷分布情况,建立了互补发电系统数学模型;其次,构建了基于信息间隙决策理论与熵权法的双层容量优化配置模型;最后,采用多元宇宙优化算法求解容量优化配置方案。算例结果表明,投资者可以根据投资意愿,对源荷不确定性采取不同的配置策略,所得的运行结果均能很好地满足不同运行模式和多种运行场景的要求;能有效地降低综合成本、提高新能源消纳能力,并且能保持抽蓄电站的长久运行。

从释意理论看电影《你好,李焕英》幽默元素字幕的翻译策略

字幕翻译是观众了解非母语影视的主要手段,优秀的字幕翻译也成为海外观众更好地了解中国电影和中国文化的重要途径。字幕翻译同口译不乏相通之处,因此源于口语实践研究、倡导脱离源语言外壳束缚的释意理论,不仅指出了译者在字幕翻译过程中应了解的原则和方向,也启发译者跳出具体翻译策略的限制,根据具体情况灵活采取合适的翻译策略,对于电影字幕翻译具有实际的指导意义。华语喜剧电影中的幽默元素体现了中国浓厚鲜明的民族文化特色,是译者较难处理的部分。电影《你好,李焕英》在翻译诸如双关语、特色方言、富有时代感的流行语和富含中国文化特色的话语这些包含幽默元素的字幕时采取了替换、归化、异化、减译等不同翻译策略。

国内外建筑围护结构风荷载规范对比研究

针对围护结构设计风荷载,分析了如下风荷载规范中的相关规定:中国GB 50009—2012、中国JGJ/T 481—2019、美国ASCE/SEI 7⁃16、日本AIJ⁃2015、澳大利亚/新西兰AS/NZS 1170.2:2021、欧洲BS EN 1991⁃1⁃4:2005、加拿大NBCC 2015。分析结果表明,国内外围护结构风荷载规范的理论基础主要包括准定常理论和风压极值理论,均将设计风荷载表示成设计风速与设计风压系数的乘积;设计风速的确定需要考虑地貌、局部地形、季节、风向、相邻建筑干扰等因素的影响,各国规范对这些因素考虑的详尽程度不一;设计风压系数则需要考虑来流湍流和特征湍流共同作用下风压的时间随机性和空间分布不均匀性、不同方向来流时建筑表面风压的差异性、建筑表面风压相关性等因素,各国规范均通过风压分区和面积折减较好地考虑了这些因素,不同之处在于不同规范所涵盖的建筑体型、考虑建筑几何参数影响的风压分区结果及面积折减的特征有所区别。