基于损伤机理的预应力混凝土梁振动频率研究
|
摘要
本文进行了两根无粘结预应力混凝土简支梁的动力试验,结果表明:随着预应力的增加,梁的频率逐渐增大,当预应力增加到一定程度时,梁的频率稍有下降。这与经典动力学理论中随着轴压力增加,梁自振频率减小的结论相反。本文从结构动力学的基本原理和损伤理论出发,对预应力混凝土梁的自振频率与预应力的关系进行了研究,利用损伤变量修正了预应力对混凝土弹性模量的影响,提出了基于损伤的预应力混凝土梁振动频率公式,计算结果表明:随着力筋预应力的变化,梁频率的变化趋势与试验结果一致,理论曲线与试验曲线符合较好,一阶频率的计算具有较高精度。在工程实践中,测出构件的振动频率即可根据本文提出的公式推算出其实际预应力的大小。
Two unbonded prestressed concrete beams were made to investigate the dynamic characteristic.The test results indicate that the frequencies of these beams are increasing gradually with the increasing of the prestress force in the certain range,then the frequencies decreasing slightly when the prestress force out of the range.While in the classical dynamics,the natural frequencies of the beams will be decreasing with the increasing of the axial force when the isotropic homogeneous materials beams bear the axial force.Thus the results from tests are inconsistent with the classical theory.Therefore,this paper embarks from the structure dynamics basic principle and the damage theory,using the elasticity coefficient change,the formula of the prestressed beam's natural frequency has been obtained.The formula results indicate that frequency changing tendency compared with test result is consistent,the result precision of the first frequency is also good.
Two unbonded prestressed concrete beams were made to investigate the dynamic characteristic.The test results indicate that the frequencies of these beams are increasing gradually with the increasing of the prestress force in the certain range,then the frequencies decreasing slightly when the prestress force out of the range.While in the classical dynamics,the natural frequencies of the beams will be decreasing with the increasing of the axial force when the isotropic homogeneous materials beams bear the axial force.Thus the results from tests are inconsistent with the classical theory.Therefore,this paper embarks from the structure dynamics basic principle and the damage theory,using the elasticity coefficient change,the formula of the prestressed beam's natural frequency has been obtained.The formula results indicate that frequency changing tendency compared with test result is consistent,the result precision of the first frequency is also good.
引文
[1]张耀庭,李宏健.全预应力砼梁动力性能试验研究[J].工程力学.2008,25(S1):71-75.
[2]Kim J T,Stubbs N.Improved damage identificationmethod based on modal information[J].Journal ofSound and Vibration,2002,252(2):223-238.
[3]李瑞鸽.全预应力梁预应力损失的动力检测研究[D].武汉:华中科技大学,2005.
[4]Farasat F,Myers MK.Extension of Kirchhoff's formu-la to radiation from moving surfaces[J].Journal ofSound and Vibration,1988,123(3):451-461.
[5]Kim Jeong-Tae,Ryu Yeon-Sun,Cho Hyun-Man,etal.Damage identification in beam-type structures:Frequency-based method vs made-shape-based method[J].Engineering Structures,2003,25(1):57-67.
[6]张耀庭,汪霞利,李瑞鸽.预应力梁固有频率的试验研究[J].华中科技大学学报(自然科学版),2007,35(2):12-15.
[7]李兆霞.损伤力学及其应用[M].北京:科学出版社,2002.
[8]王军.损伤力学的理论与应用[M].北京:科学出版社,1997.
[9]Lemaitre J.损伤力学教程(中译本)[M].北京:科学出版社,1996.
[10]余天庆,钱济成.损伤理论及其应用[M].北京:国防工业出版社,1993.
[11]李东旭.高等结构动力学[M].长沙:国防科技大学出版社,1997.
[12]杜思义,殷学纲,张卫民.基于摄动有限元方法对梁结构损伤的识别[J].世界地震工程.2006,22(2):114-118.
[13]Saiidi M,Douglas B,Feng S.Prestress force effect onvibration frequency of concrete bridges[J].Journal ofStructural Engineering,1994,120(7):2233-2241.
[2]Kim J T,Stubbs N.Improved damage identificationmethod based on modal information[J].Journal ofSound and Vibration,2002,252(2):223-238.
[3]李瑞鸽.全预应力梁预应力损失的动力检测研究[D].武汉:华中科技大学,2005.
[4]Farasat F,Myers MK.Extension of Kirchhoff's formu-la to radiation from moving surfaces[J].Journal ofSound and Vibration,1988,123(3):451-461.
[5]Kim Jeong-Tae,Ryu Yeon-Sun,Cho Hyun-Man,etal.Damage identification in beam-type structures:Frequency-based method vs made-shape-based method[J].Engineering Structures,2003,25(1):57-67.
[6]张耀庭,汪霞利,李瑞鸽.预应力梁固有频率的试验研究[J].华中科技大学学报(自然科学版),2007,35(2):12-15.
[7]李兆霞.损伤力学及其应用[M].北京:科学出版社,2002.
[8]王军.损伤力学的理论与应用[M].北京:科学出版社,1997.
[9]Lemaitre J.损伤力学教程(中译本)[M].北京:科学出版社,1996.
[10]余天庆,钱济成.损伤理论及其应用[M].北京:国防工业出版社,1993.
[11]李东旭.高等结构动力学[M].长沙:国防科技大学出版社,1997.
[12]杜思义,殷学纲,张卫民.基于摄动有限元方法对梁结构损伤的识别[J].世界地震工程.2006,22(2):114-118.
[13]Saiidi M,Douglas B,Feng S.Prestress force effect onvibration frequency of concrete bridges[J].Journal ofStructural Engineering,1994,120(7):2233-2241.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心