结构基频对冷却塔风振效应的影响
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摘要
为明确结构基频f0对冷却塔风振效应的影响,以某大型冷却塔为例,在风振响应时程计算和风振效应特征分析的基础上,通过调整材料弹性模量E实现对f0的改变,以单独分析f0对风振效应尤其是共振分量?R的影响,并阐述了该方法的优点。结果表明,根据共振与背景分量?R、?B在时域内的分离方法,不管f0如何变化,?R与?B之间的耦合分量始终可以忽略。各响应?R随f0的降低而增加,并在f0小于0.7 Hz以后急剧增加,但因?B在总脉动响应?T中贡献较高,故?T和阵风响应因子GRF仅在f0小于0.5 Hz以后才有较明显的增加。各响应?R随f0的降低而增加的原因在于风谱能量随频率的降低而增加,且结构f0越小其共振参与模态越多。为方便评价共振响应?R随f0的变化,提出参数RP=(1/f0×(1/f0?1/2))综合考虑以上两种因素作为?R的评价指标,且各响应的?R与RP均呈线性变化。
Studies were initiated for clear interpretation of the influence of the fundamental frequency, f0, on the wind dynamic effects of hyperbolic cooling towers(HCTs). Based on the preceding wind dynamic calculation in time domain and the features of dynamic effects, a new method was proposed to adjust f0 and brought into the following operation. In this new method, the material elastic modulus E was changed to get different f0's and corresponding wind dynamic effects, especially the resonance component, ?R. The advantages of this method are also presented. The results show that the coupling effect between the resonance and background components, ?R and ?B, obtained in time domain is negligible no matter what value the f0 takes. ?R increases with the decrease of f0, especially when f0 is less than 0.7 Hz. However, the total gust response, ?T, increases more slowly with the decrease of f0 because the significant contribution of ?B and ?B does not change with f0. Therefore, ?T shows quick increase only if f0 is less than 0.5 Hz. There are two reasons for the increase of ?R when f0 decreases: 1) the wind spectrum increases with the decrease of frequency and 2) more resonant modes would be excited. A parameter RP=(1/f0×(1/f0?1/2)), which could cover the above two reasons, was proposed for convenient evaluation of ?R. A linear relationship is found between ?R of all responses and the parameter RP.
Studies were initiated for clear interpretation of the influence of the fundamental frequency, f0, on the wind dynamic effects of hyperbolic cooling towers(HCTs). Based on the preceding wind dynamic calculation in time domain and the features of dynamic effects, a new method was proposed to adjust f0 and brought into the following operation. In this new method, the material elastic modulus E was changed to get different f0's and corresponding wind dynamic effects, especially the resonance component, ?R. The advantages of this method are also presented. The results show that the coupling effect between the resonance and background components, ?R and ?B, obtained in time domain is negligible no matter what value the f0 takes. ?R increases with the decrease of f0, especially when f0 is less than 0.7 Hz. However, the total gust response, ?T, increases more slowly with the decrease of f0 because the significant contribution of ?B and ?B does not change with f0. Therefore, ?T shows quick increase only if f0 is less than 0.5 Hz. There are two reasons for the increase of ?R when f0 decreases: 1) the wind spectrum increases with the decrease of frequency and 2) more resonant modes would be excited. A parameter RP=(1/f0×(1/f0?1/2)), which could cover the above two reasons, was proposed for convenient evaluation of ?R. A linear relationship is found between ?R of all responses and the parameter RP.
引文
[1]张军锋,朱冰,葛耀君,等.冷却塔风振效应特征及影响因素分析[J].振动与冲击,2018,37(18):201―208.Zhang Junfeng,Zhu Bing,Ge Yaojun,et al.Features of wind dynamic effects of a hyperboloidal cooling tower and the influence factors[J].Journal of Vibration and Shock,2018,37(18):201―208.(in Chinese)
[2]Ke S T,Ge Y J,Zhao,L.Wind-induced vibration characteristics and parametric analysis of large hyperbolic cooling towers with different feature sizes[J].Structural Engineering and Mechanics,2015,54(5):891―908.
[3]Singh M P,Gupta A K.Gust factors for hyperbolic cooling towers[J].Journal of the Structural Division,1976,102(2):371―386.
[4]卢文达,王养琪,蓬静欣,等.双曲冷却塔的阵风响应[J].中国电机工程学报,1982(1):45―61.Lu Wenda,Wang Yangqi,Peng Jingxin,et al.Response of hyperbolic cooling tower to turbulent wind[J].Proceedings of the CSEE,1982(1):45―61.(in Chinese)
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[6]张军锋,葛耀君,赵林,等.双曲冷却塔表面三维绕流特性及风压相关性研究[J].工程力学,2013,30(9):234―242.Zhang Junfeng,Ge Yaojun,Zhao Lin,et al.Wind tunnel study on the three dimensional flow and spatial correlation properties of wind loads on hyperboloidal cooling towers[J].Engineering Mechanics,2013,30(9):234―242.(in Chinese)
[7]Noh S Y,Lee S Y.Evaluation of the natural draught cooling tower shell using linearly and non-linearly numerical analysis[J].Journal of vibroengineering,2012,14(3):1011―1020.
[8]鲍侃袁.大型双曲冷却塔的风荷载和风致响应理论分析与试验研究[D].杭州:浙江大学,2009.Bao Kanyuan.Theoretical and experimental research on wind load and wind induced response of large hyperbolic cooling towers[D].Hangzhou:Zhejiang University,2009.(in Chinese)
[9]Zhang JunFeng,Chen Huai,Ge YaoJun,et al.Effects of stiffening rings on the dynamic properties of hyperboloidal cooling towers[J].Structural Engineering and Mechanics,2014,49(5):619―629.
[10]张军锋,葛耀君,赵林.双曲冷却塔结构特性新认识[J].工程力学,2013,30(6):67―76.Zhang Junfeng,Ge Yaojun,Zhao Lin.New perceptions on the structure behavior of hyperboloidal cooling towers[J].Engineering Mechanics,2013,30(6):67―76.(in Chinese)
[11]Busch D,Harte R,Niemann H J.Study of a proposed200m high natural draught cooling tower at power plant Frimmersdorf/Germany[J].Eng.Struct.,1998,20(10),920―927.
[12]邹云峰,牛华伟,陈政清.基于完全气动弹性模型的冷却塔风致响应风洞试验研究[J].建筑结构学报,2013,34(6):60―67.Zou Yunfeng,Niu Huawei,Chen Zhengqing.Wind tunnel test on wind-induced response of cooling tower based on full aero-elastic model[J].Journal of Building Structures,2013,34(6):60―67.(in Chinese)
[13]赵海,白国良,徐亚洲,等.初始缺陷对超大型双曲冷却塔极限承载力的影响[J].西安建筑科技大学学报(自然科学版),2011,43(6):777―783.Zhao Hai,Bai Guoliang,Xu Yazhou,et al.The influence of initial imperfections on the ultimate bearing capacity of super-large hyperbolic cooling tower[J].Journal of Xi’an University of Architecture and Technique(Natural Science Edition),2011,43(6):777―783.(in Chinese)
[14]张军锋,丁玉玺,陈淮.冷却塔塔筒荷载效应和简化设计方法―配筋计算流程的简化[J].防灾减灾工程学报,2018,38(3):549―555.Zhang Junfeng,Ding Yuxi,Chen Huai.Load effects and load effects combination of hyperbolidial cooling tower shell-A simplified combination method[J].Journal of Disaster Prevention and Mitigation Engineering,2018,38(3):549―555.(in Chinese)
[15]Davenport A G.Gust loading factors[J].Journal of the Structural Division,1967,93(3):11―34.
[16]Clough R W,Penzien J.Dynamics of structures[M].3rd ed.Computers&Structures,2003.
[17]VGB-Guideline:structural design of cooling towertechnical guideline for the structural design,computation and execution of cooling towers(VGB-R 610Ue)[S].Essen:BTR Bautechnik bei Kühltürmen,2005.
[18]BS 4485 Part 4.Code of practice for structural design and construction-water cooling towers[S].London:British Standard Institution,1996.
[19]Armitt J.Wind loading on cooling towers[J].Journal of the Structural Division,1980,106(3):623―641.
[20]Niemann H J.Wind effects on cooling-tower shells[J].Journal of the Structural Division,1980,106(3):643―661.
[21]Zhou Y,Kijewski T,Kareem A.Along-wind load effects on tall buildings:comparative study of major international codes and standards[J].Journal of Structural Engineering,2002,128(6):788―796.
[2]Ke S T,Ge Y J,Zhao,L.Wind-induced vibration characteristics and parametric analysis of large hyperbolic cooling towers with different feature sizes[J].Structural Engineering and Mechanics,2015,54(5):891―908.
[3]Singh M P,Gupta A K.Gust factors for hyperbolic cooling towers[J].Journal of the Structural Division,1976,102(2):371―386.
[4]卢文达,王养琪,蓬静欣,等.双曲冷却塔的阵风响应[J].中国电机工程学报,1982(1):45―61.Lu Wenda,Wang Yangqi,Peng Jingxin,et al.Response of hyperbolic cooling tower to turbulent wind[J].Proceedings of the CSEE,1982(1):45―61.(in Chinese)
[5]张军锋,葛耀君,赵林.冷却塔风振响应时程计算与风振系数分析[J].振动与冲击,2017,36(3):163―171.Zhang Junfeng,Ge Yaojun,Zhao Lin.Wind induced responses of a hyperboloidal cooling tower in time-domain and the gust effect factor analysis[J].Journal of Vibration and Shock,2017,36(3):163―171.(in Chinese)
[6]张军锋,葛耀君,赵林,等.双曲冷却塔表面三维绕流特性及风压相关性研究[J].工程力学,2013,30(9):234―242.Zhang Junfeng,Ge Yaojun,Zhao Lin,et al.Wind tunnel study on the three dimensional flow and spatial correlation properties of wind loads on hyperboloidal cooling towers[J].Engineering Mechanics,2013,30(9):234―242.(in Chinese)
[7]Noh S Y,Lee S Y.Evaluation of the natural draught cooling tower shell using linearly and non-linearly numerical analysis[J].Journal of vibroengineering,2012,14(3):1011―1020.
[8]鲍侃袁.大型双曲冷却塔的风荷载和风致响应理论分析与试验研究[D].杭州:浙江大学,2009.Bao Kanyuan.Theoretical and experimental research on wind load and wind induced response of large hyperbolic cooling towers[D].Hangzhou:Zhejiang University,2009.(in Chinese)
[9]Zhang JunFeng,Chen Huai,Ge YaoJun,et al.Effects of stiffening rings on the dynamic properties of hyperboloidal cooling towers[J].Structural Engineering and Mechanics,2014,49(5):619―629.
[10]张军锋,葛耀君,赵林.双曲冷却塔结构特性新认识[J].工程力学,2013,30(6):67―76.Zhang Junfeng,Ge Yaojun,Zhao Lin.New perceptions on the structure behavior of hyperboloidal cooling towers[J].Engineering Mechanics,2013,30(6):67―76.(in Chinese)
[11]Busch D,Harte R,Niemann H J.Study of a proposed200m high natural draught cooling tower at power plant Frimmersdorf/Germany[J].Eng.Struct.,1998,20(10),920―927.
[12]邹云峰,牛华伟,陈政清.基于完全气动弹性模型的冷却塔风致响应风洞试验研究[J].建筑结构学报,2013,34(6):60―67.Zou Yunfeng,Niu Huawei,Chen Zhengqing.Wind tunnel test on wind-induced response of cooling tower based on full aero-elastic model[J].Journal of Building Structures,2013,34(6):60―67.(in Chinese)
[13]赵海,白国良,徐亚洲,等.初始缺陷对超大型双曲冷却塔极限承载力的影响[J].西安建筑科技大学学报(自然科学版),2011,43(6):777―783.Zhao Hai,Bai Guoliang,Xu Yazhou,et al.The influence of initial imperfections on the ultimate bearing capacity of super-large hyperbolic cooling tower[J].Journal of Xi’an University of Architecture and Technique(Natural Science Edition),2011,43(6):777―783.(in Chinese)
[14]张军锋,丁玉玺,陈淮.冷却塔塔筒荷载效应和简化设计方法―配筋计算流程的简化[J].防灾减灾工程学报,2018,38(3):549―555.Zhang Junfeng,Ding Yuxi,Chen Huai.Load effects and load effects combination of hyperbolidial cooling tower shell-A simplified combination method[J].Journal of Disaster Prevention and Mitigation Engineering,2018,38(3):549―555.(in Chinese)
[15]Davenport A G.Gust loading factors[J].Journal of the Structural Division,1967,93(3):11―34.
[16]Clough R W,Penzien J.Dynamics of structures[M].3rd ed.Computers&Structures,2003.
[17]VGB-Guideline:structural design of cooling towertechnical guideline for the structural design,computation and execution of cooling towers(VGB-R 610Ue)[S].Essen:BTR Bautechnik bei Kühltürmen,2005.
[18]BS 4485 Part 4.Code of practice for structural design and construction-water cooling towers[S].London:British Standard Institution,1996.
[19]Armitt J.Wind loading on cooling towers[J].Journal of the Structural Division,1980,106(3):623―641.
[20]Niemann H J.Wind effects on cooling-tower shells[J].Journal of the Structural Division,1980,106(3):643―661.
[21]Zhou Y,Kijewski T,Kareem A.Along-wind load effects on tall buildings:comparative study of major international codes and standards[J].Journal of Structural Engineering,2002,128(6):788―796.