The surge in demand for renewable energy to combat the ever-escalating climate crisis promotes development of the energy-saving,carbon saving and reduction technologies.Shallow ground-source heat pump(GSHP)system is a...The surge in demand for renewable energy to combat the ever-escalating climate crisis promotes development of the energy-saving,carbon saving and reduction technologies.Shallow ground-source heat pump(GSHP)system is a promising carbon reduction technology that can stably and effectively exploit subsurface geothermal energy by taking advantage of load-bearing structural elements as heat transfer medium.However,the transformation of conventional geo-structures(e.g.piles)into heat exchangers between the ground and superstructures can potentially induce variable thermal axial stresses and displacements in piles.Traditional energy pile analysis methods often rely on deterministic and homogeneous soil parameter profiles for investigating thermo-mechanical soil-structure interaction,without consideration of soil spatial variability,model uncertainty or statistical uncertainty associated with interpolation of soil parameter profiles from limited site-specific measurements.In this study,a random finite difference model(FDM)is proposed to investigate the thermo-mechanical load-transfer mechanism of energy piles in granular soils.Spatially varying soil parameter profile is interpreted from limited site-specific measurements using Bayesian compressive sensing(BCS)with proper considering of soil spatial variability and other uncertainties in the framework of Monte Carlo simulation(MCS).Performance of the proposed method is demonstrated using an illustrative example.Results indicate that the proposed method enables an accurate evaluation of thermally induced axial stress/displacement and variation in null point(NP)location with quantified uncertainty.A series of sensitivity analyses are also carried out to assess effects of the pile-superstructure stiffness and measurement data number on the performance of the proposed method,leading to useful insights.展开更多
针对齿轮箱的振动噪声问题,提出了一种基于齿轮载荷静态传递误差(load static transfer error,LSTE)优化的减振降噪方法。通过建立齿廓修形齿轮的时变啮合刚度解析模型,并采用Timoshenko梁单元构建齿轮-转子-轴承耦合动力学模型,系统揭...针对齿轮箱的振动噪声问题,提出了一种基于齿轮载荷静态传递误差(load static transfer error,LSTE)优化的减振降噪方法。通过建立齿廓修形齿轮的时变啮合刚度解析模型,并采用Timoshenko梁单元构建齿轮-转子-轴承耦合动力学模型,系统揭示了不同修形量和修形曲线下齿轮LSTE与系统动力学响应之间的关系。在此基础上,采用遗传算法对齿轮LSTE相对峰峰值进行优化,获得最优修形参数组合。最后结合有限元/边界元法,分析了修形优化前后齿轮箱的噪声辐射特性。研究结果表明,经遗传算法优化后的修形参数可使主动轮位移幅频响应幅值与加速度幅频响应幅值相较其他修形参数均显著降低,齿轮箱辐射声功率级均方根值由未修形时的38.66 dB降至修形优化后25.32 dB,降幅达34.51%,降噪效果显著。研究成果为齿轮传动系统的低噪声设计提供了理论依据。展开更多
为减少高层装配式住宅的竖向变形,满足工程的实际使用功能,以山东省山东大学某26层装配整体式混凝土剪力墙住宅项目为研究对象,通过对变形情况进行模拟并对比实际施工情况,分析其变形发展变化的内在原因,包括:地基沉降、混凝土收缩徐变、...为减少高层装配式住宅的竖向变形,满足工程的实际使用功能,以山东省山东大学某26层装配整体式混凝土剪力墙住宅项目为研究对象,通过对变形情况进行模拟并对比实际施工情况,分析其变形发展变化的内在原因,包括:地基沉降、混凝土收缩徐变、预制构件连接工艺缺陷、短期施工荷载过早施加及温度应力等因素。采用建筑信息模型(building information modeling,BIM)+激光扫描实施纠偏技术、施工准备阶段三维可视化交底、施工阶段双重精度检测对比纠偏,结合沉降观测、施工预抛高等辅助措施,使竖向变形量降至10 mm,满足规范要求,并缩短了工期、降低了成本,验证了控制措施的有效性。展开更多
基金The work described in this paper was supported by grants from the Research Grant Council of Hong Kong Special Administrative Region,China(Grants Nos.CityU 11213119 and CityU 11202121).The financial support is gratefully acknowledged.
文摘The surge in demand for renewable energy to combat the ever-escalating climate crisis promotes development of the energy-saving,carbon saving and reduction technologies.Shallow ground-source heat pump(GSHP)system is a promising carbon reduction technology that can stably and effectively exploit subsurface geothermal energy by taking advantage of load-bearing structural elements as heat transfer medium.However,the transformation of conventional geo-structures(e.g.piles)into heat exchangers between the ground and superstructures can potentially induce variable thermal axial stresses and displacements in piles.Traditional energy pile analysis methods often rely on deterministic and homogeneous soil parameter profiles for investigating thermo-mechanical soil-structure interaction,without consideration of soil spatial variability,model uncertainty or statistical uncertainty associated with interpolation of soil parameter profiles from limited site-specific measurements.In this study,a random finite difference model(FDM)is proposed to investigate the thermo-mechanical load-transfer mechanism of energy piles in granular soils.Spatially varying soil parameter profile is interpreted from limited site-specific measurements using Bayesian compressive sensing(BCS)with proper considering of soil spatial variability and other uncertainties in the framework of Monte Carlo simulation(MCS).Performance of the proposed method is demonstrated using an illustrative example.Results indicate that the proposed method enables an accurate evaluation of thermally induced axial stress/displacement and variation in null point(NP)location with quantified uncertainty.A series of sensitivity analyses are also carried out to assess effects of the pile-superstructure stiffness and measurement data number on the performance of the proposed method,leading to useful insights.
文摘为减少高层装配式住宅的竖向变形,满足工程的实际使用功能,以山东省山东大学某26层装配整体式混凝土剪力墙住宅项目为研究对象,通过对变形情况进行模拟并对比实际施工情况,分析其变形发展变化的内在原因,包括:地基沉降、混凝土收缩徐变、预制构件连接工艺缺陷、短期施工荷载过早施加及温度应力等因素。采用建筑信息模型(building information modeling,BIM)+激光扫描实施纠偏技术、施工准备阶段三维可视化交底、施工阶段双重精度检测对比纠偏,结合沉降观测、施工预抛高等辅助措施,使竖向变形量降至10 mm,满足规范要求,并缩短了工期、降低了成本,验证了控制措施的有效性。
