GENERAL SOLUTION FOR DYNAMICAL PROBLEM OF INFINITE BEAM ON AN ELASTIC FOUNDATION

Based on the theory of Eider-Bernoulli beam and Winkler assumption for elastic foundation, a mathematical model is presented. By using Fourier transformation for space variable, Laplace transformation for time variable and convolution theorem for their inverse transformations, a general solution for dynamical problem of infinite beam on an elastic foundation is obtained. Finally, the cases of free vibration,impulsive response and moving load are also discussed.

Integration of GIS with the Generalized Reciprocal Method(GRM)for Determining Foundation Bearing Capacity:A Case Study in Opolo,Yenagoa Bayelsa State,Nigeria

This study addresses the pressing need to assess foundation bearing capacity in Opolo,Yenagoa,Bayelsa State,Nigeria.The significance lies in the dearth of comprehensive geotechnical data for construction planning in the region.Past research is limited and this study contributes valuable insights by integrating Geographic Information System(GIS)with the Generalized Reciprocal Method(GRM).To collect data,near-surface seismic refraction surveys were conducted along three designated lines,utilizing ABEM Terraloc Mark 6 equipment,Easy Refract,and ArcGIS 10.4.1 software.This methodology allowed for the determination of key geotechnical parameters essential for soil characterization at potential foundation sites.The results revealed three distinct geoseismic layers.The uppermost layer,within a depth of 0.89 to 1.50 meters,exhibited inadequate compressional and shear wave velocities and low values for oedometric modulus,shear modulus,N-value,ultimate bearing capacity,and allowable bearing capacity.This indicates the presence of unsuitable,soft,and weak alluvial deposits for substantial structural loads.In contrast,the second layer(1.52 to 3.84 m depth)displayed favorable geotechnical parameters,making it suitable for various construction loads.The third layer(15.00 to 26.05 m depth)exhibited varying characteristics.The GIS analysis highlighted the unsuitability of the uppermost layer for construction,while the second and third layers were found to be fairly competent and suitable for shallow footing and foundation design.In summary,this study highlights the importance of geotechnical surveys in Opolo’s construction planning.It offers vital information for informed choices,addresses issues in the initial layer,and suggests secure,sustainable construction options.

Unified two-phase nonlocal formulation for vibration of functionally graded beams resting on nonlocal viscoelastic Winkler-Pasternak foundation

A nonlocal study of the vibration responses of functionally graded(FG)beams supported by a viscoelastic Winkler-Pasternak foundation is presented.The damping responses of both the Winkler and Pasternak layers of the foundation are considered in the formulation,which were not considered in most literature on this subject,and the bending deformation of the beams and the elastic and damping responses of the foundation as nonlocal by uniting the equivalently differential formulation of well-posed strain-driven(ε-D)and stress-driven(σ-D)two-phase local/nonlocal integral models with constitutive constraints are comprehensively considered,which can address both the stiffness softening and toughing effects due to scale reduction.The generalized differential quadrature method(GDQM)is used to solve the complex eigenvalue problem.After verifying the solution procedure,a series of benchmark results for the vibration frequency of different bounded FG beams supported by the foundation are obtained.Subsequently,the effects of the nonlocality of the foundation on the undamped/damping vibration frequency of the beams are examined.

Free-Form Laminated Doubly-Curved Shells and Panels of Revolution Resting on Winkler-Pasternak Elastic Foundations: A 2-D GDQ Solution for Static and Free Vibration Analysis

This work presents the static and dynamic analyses of laminated doubly-curved shells and panels of revolution resting on Winkler-Pasternak elastic foundations using the Generalized Differential Quadrature (GDQ) method. The analyses are worked out considering the First-order Shear Deformation Theory (FSDT) for the above mentioned moderately thick structural elements. The effect of the shell curvatures is included from the beginning of the theory formulation in the kinematic model. The solutions are given in terms of generalized displacement components of points lying on the middle surface of the shell. Simple Rational Bézier curves are used to define the meridian curve of the revolution structures. The discretization of the system by means of the GDQ technique leads to a standard linear problem for the static analysis and to a standard linear eigenvalue problem for the dynamic analysis. Comparisons between the present formulation and the Reissner-Mindlin theory are presented. Furthermore, GDQ results are compared with those obtained by using commercial programs. Very good agreement is observed. Finally, new results are presented in order to investtigate the effects of the Winkler modulus, the Pasternak modulus and the inertia of the elastic foundation on the behavior of laminated shells of revolution.

Application of Generalized Non-Local Quantum Hydrodynamics to the Calculation of the Charge Inner Structures for Proton and Electron

The proton and electron charge inner structures are considered in the frame of the non-local quantum hydrodynamics based on the non-local physical description. From calculations follow that proton and electron can be considered like charged balls (shortly CB model) which charges are concentrated mainly in the shell of these balls. The proton-electron collision in the frame of CB-model should be considered as collision of two resonators. In this case can be explained a number of character collisional features depending on the initial and final electron energies and the scattering angles.

生成式人工智能大模型赋能传统出版企业转型升级路径研究——基于扎根理论的质性研究

基于质性研究方法,通过扎根理论提炼归纳出“智能内容生成提质优化、产业生产效率提速升级、个性定制内容交付传播、融合发布渠道策略制定、商业市场数据分析洞察、新型商业模式开发创新、组织架构流程变革重组、品牌核心价值维护创造、法律法规伦理风险考量”九大主范畴和“传统出版企业转型升级”一大核心范畴。在对主范畴与核心范畴的典型关系结构以及范畴间逻辑关系分析的基础上,构建生成式人工智能大模型赋能传统出版企业转型升级有效路径的理论模型。模型揭示了如何更好地将生成式人工智能大模型赋能企业后端的生产力提升和前端的新价值创造是传统出版企业实现转型升级的关键。

地铁盾构下穿高铁站房安全监测

针对地铁盾构下穿地表建筑物形变规律监测和复杂工况环境下地基SAR数据处理等问题,提出利用广义离群检验算法对地基SAR一阶差分相位数据进行粗差探测与剔除,联合地基SAR与测量机器人监测数据对地铁盾构下穿湘潭北站高铁站房进行形变监测与安全分析,并基于力学模型和Flac3D软件进行数值模拟,较好的得出盾构下穿高铁站房各阶段形变特征与规律。结果表明,广义离群检验算法有效解决了复杂工况环境下地基SAR数据遮挡问题,联合测量机器人数据得到与数值模型变形解算结果一致,且符合施工过程物理力学客观规律,基本实现盾构下穿地表建筑物安全监测,为类似地铁盾构安全施工检测提供参考。

从基础智能到通用智能:基于大模型的GenAI和AGI之现状与展望

本文对生成式AI(Generative artificial intelligence,GenAI)的国内外发展现状进行了概述,重点分析了中美之间在算力、数据、算法、生态等方面存在的差距.为改变我国在生成式AI领域的落后现状,提出高能效算力建设、联邦数据、专业领域模型、基于TAO的联邦生态等应对策略,对大模型时代AI安全治理进行了论述,对通用人工智能(Artificial general intelligence,AGI)的未来发展进行了展望.

桩撑式支护基坑通用弹性地基梁分析法

弹性地基梁法常用于模拟分析桩撑(锚)式支护基坑在开挖、设撑等施工工况中变形和受力的变化。目前利用该方法对某工况基坑分析时,首先要将整个支护桩在支撑处划分为若干个桩段,然后利用相邻桩段交界处的位移连续条件和受力平衡条件,推导出相应的待定参数方程,之后再利用求出的待定参数分析支护体系(基坑)的变形和受力。由于不同施工工况对应的支撑数和桩段数不同,因此该方法必须根据不同工况重新推导各自的参数方程,从而导致计算过程繁杂,难以形成通用计算公式和方法,也不易编程等问题。通过将支撑与桩段归纳为3种基本连接形式(即支撑分别相连于桩顶、相邻两桩段之间和坑底),本文建立了相邻两个桩段间待定参数的递推公式,进而推导出了适用于内支撑和锚索支撑形式、任意支撑道数、开挖或设撑工况的通用待定参数方程。该方程仅含4个参数,远少于现有方法且易于求解。文中算例结果验证了本文方法的合理性和可行性。

生成式人工智能赋能高校思想政治教育的理论基础、现实应用、潜在风险及优化对策研究

生成式人工智能(AIGC)的出现虽然为高校思想政治教育的变革提供了新的技术实现路径,但也存在潜在风险。AIGC在初步理解人类语言、体会情感、模仿思维、提供决策方面为其赋能高校思想政治教育提供可能,并为高校思想政治教育观念、教育内容、教育方法创新上带来了机遇。与此同时存在淡化思想政治教育内容的接受度、泛化思想政治教育目标的明确度、弱化思想政治教育主体地位、虚化思想政治教育载体功能的风险。因此,需要各界协同发力,优化算法推荐,提高思想政治教育内容的精准性;丰富数据来源,夯实思想政治教育的主流价值引导;避免技术滥用,强化思想政治教育的人文关怀;坚持人民至上,探索人机协同的育人模式。

新型深海风机钢管桩基础安装用导向架结构优化

为解决水深45.000 m深海风机钢管桩基础安装作业可靠性差和精度低等问题,对一种新型深海风机钢管桩基础安装用导向架进行结构优化。采用有限元法(Finite Element Method, FEM)与试验相结合的方法,从环境参数与作用载荷、结构形式、作业工况和结构强度与结构稳定性等方面对导向架进行综合研究。经海试验证,优化的导向架的打桩精度与打桩高效性均满足技术指标要求,可大幅提高深海风机钢管桩基础安装作业速度和质量。

基于大模型的教学智能体构建与应用研究

随着生成式人工智能的快速发展,基于大模型的智能体已经逐步具备了多模态感知、检索增强生成、推理与规划、交互与进化等能力。该研究提出基于大模型的教学智能体的基本概念与框架,以“大模型”为技术核心,重点构建“教育任务设定”“教育任务规划”“教育能力实现与拓展”“教育内容记忆与反思”“交互协作与动态进化”多个功能模块,支持与多类型对象交互并实现动态进化,涵盖人机交互、多智能体交互以及环境交互。基于所提出的框架,研究以项目式学习任务为应用场景,阐述了教学智能体作为“助教智能体”和“同伴智能体”,在个性化驱动问题提出、项目方案共同设计、项目作品协作完成、项目作品多角色评价多个环节的作用及相关支撑技术。最后,研究进一步探讨了教学智能体的发展方向与未来展望。

大模型创新变革:新模式、新挑战与新趋势

生成式人工智能的出现给传统创新范式带来新挑战,引发各界对创新管理理论和创新实践的前瞻性讨论,审视并应对大模型所带来的创新变革富有积极意义。首先,基于人工智能创新进展,探索从传统人工智能到生成式人工智能的研发创新模式变化,识别大模型研发创新的核心特性;其次,探究大模型对知识管理、科学研究、技术创新和产业创新等理论带来的新挑战,并阐释基本逻辑和核心指向。最后,从大模型内在创新规律、知识管理创新、科研组织方式、技术创新范式以及产业创新生态5个方面提出未来研究方向。研究结论不仅有助于明确大模型所带来的创新挑战,还对加快大模型创新理论研究具有参考价值。

库水-淤砂层-坝体-坝基体系地震响应分析

针对我国西部水利工程结构面临的地震安全问题,特别是混凝土高拱坝的抗震安全设计,以小湾水电站混凝土高拱坝为研究对象,进行了库水-淤砂层-坝体-坝基体系的耦合动力分析,同时考虑了复杂的坝基地形、正常蓄水位的库水以及常年运行而堆积的淤沙层的影响。主要内容有:①基于传递矩阵法及二维有限元,实现了复杂峡谷地形的自由场计算;②基于水-饱和多孔介质-固体的统一计算框架,实现了库水-淤沙层-坝体-坝基体系的三维地震响应分析算法。最后,分别以脉冲波和地震波作为输入,探讨了小湾拱坝的地震响应规律及库水淤沙层对拱坝地震响应的影响。结果表明:坝体顶部中心区域会承受较大的拉、压应力;而库水底部淤砂层对坝体的位移及应力影响并不显著。

基于广义Voigt模型的半渗透边界隧道周围饱和软土固结分析

引入衬砌半渗透边界条件,使用广义Voigt黏弹性模型描述隧道周围饱和软黏土的流变特性,基于Terzaghi-Rendulic理论建立以超孔隙水压力为变量的软土二维流变固结控制方程。采用保角变换和分离变量方法,得到超孔隙水压力关于时间和空间变量的两个独立方程,依次使用Laplace变换法与部分分式展开法得到时域内超孔隙水压力消散解。将广义Voigt模型退化为已有四元件Burgers模型和五元件模型并与其对比,验证解答的可靠性。基于建立的解答,分析衬砌透水程度、Kelvin体数量、独立Newton黏壶黏滞系数、隧道埋深等因素对超孔隙水压力消散与分布的影响规律。结果表明:衬砌与土体的相对渗透系数比越大,超孔隙水压力的消散起始时间越早,消散速度越快。Kelvin体数量越多,超孔隙水压力消散越慢;独立黏壶黏滞系数越大,其产生的黏滞变形越小,超孔隙水压力消散速率越快;隧道埋深越大,土体渗流路径越长,超孔隙水压力消散越慢;当相对渗透系数比为0.01时,超孔隙水压力随着到隧道外壁距离的增大而逐渐减小,当相对渗透系数比为1.00时,超孔隙水压力随着距离的增大而出现先增大后减小的现象;随着相对渗透系数比的增加,Kelvin体数量对超孔压消散的影响越小,不同独立黏滞系数带来的超孔压消散差异逐渐减小,隧道衬砌作为土层内部新透水边界的作用越突出。

Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent years.Bamboo fibers are renowned for their good mechanical properties,abundance,and short cycle growth.As beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic foundation.Three different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the thickness.The elastic properties of the composite are determined with the law of mixture.Employing Hamilton’s principle,the governing equations of motion are obtained.The generalized differential quadrature method(GDQM)is then applied to the equations to obtain the results.The achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam change.Furthermore,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber distribution.Eventually,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

基于变形监测成果的基坑支护设计稳定性评价

采用粒子群算法、广义回归神经网络和差分自回归移动平均模型实现基坑变形预测,评价基坑施工过程中的稳定性,以佐证基坑支护措施的有效性。基坑区地质条件、近接条件均较为复杂,需采用刚度大的支护结构来控制基坑变形,因此,将基坑支护形式确定为桩锚支护结构,且为确保基坑支护体系的经济性,还进行了分区支护措施设计。在基坑稳定性评价过程中,现阶段条件下的沉降变形的变化范围为12.68~21.42 mm,均值为17.84 mm,水平位移的变化范围为15.08~22.49 mm,均值为18.68 mm,得出两类变形均小于变形控制值,说明基坑目前的变形在变形控制值范围内,其稳定性较好;通过变形预测,得出基坑后续变形具收敛趋势,后续的变形值范围为21.35~23.58 mm,也小于变形控制值,说明基坑后续的变形控制也较好,基坑稳定性较优。

基于粒子群优化的小波神经网络算法及风机基础监测应用

安全监测是大型风机建筑物的健康保障。由于风机往往处于复杂环境,对其基础的沉降监测和预报非常重要。而传统预报方法存在精度低、可靠性差等局限性。以某风机基础多期沉降监测数据为例,给出15台风机基础各18个监测点的竖向位移。同时,利用粒子群算法对小波神经网络进行全局参数寻优,建立风机基础的竖向位移预报模型。结果表明,基于粒子群优化的小波神经网络算法的预报精度比传统灰色模型方法和小波神经网络方法分别提高22.9%和4.4%。

西藏自治区超高海拔牧区光伏支架桩基础的施工质量控制研究

西藏自治区超高海拔牧区的气候环境、地质条件、环保要求等与内地的不同,因此在此类地区建设光伏电站时,光伏支架桩基础施工时需要考虑的因素,以及设备、材料等的选择也存在很大差异。以西藏山南曲松罗布沙850 MW牧光互补光伏发电项目中光伏支架桩基础的施工为例,对西藏自治区超高海拔牧区光伏支架桩基础的施工质量控制开展研究。首先结合项目所在地的地质条件和环保要求,选择出最合适的桩基础类型;其次对光伏场区内3种施工设备的施工效率、经济性、稳定性、环保性进行了比较;最后通过严格落实施工工艺及采用钢丝绳定位的方式确保了桩基础的施工质量。研究结果表明:此类地区的光伏支架桩基础采用“以螺旋钢桩基础为主、微孔灌注桩基础为辅”的方案,能同时满足环境保护、施工效率和力学性能的要求;为确保施工进度,施工设备可选择240型普通挖改钻机;介绍的螺旋钢桩基础和微孔灌注桩基础的施工工艺及施工质量控制措施效率高、效果明显,能确保桩基础施工后的力学性能满足设计要求。研究结果为其他同类型光伏发电项目桩基础的施工提供了可借鉴的经验。