Study The Wind-induced Responses And The Wind Induced Vibration Reliability Of Cross Rope Transmission Tower Line System In Strong Wind Region

The free-standing transmission tower is the form of tower structure,which is often used in UHV transmission lines, This type of transmission tower structure has characteristics of more steel,high cost,complex construction process,long time building, kentucky area relatively small etc,which is usually only suitable for surround of the cities and mountainous hilly region, due to flat terrains,vast area of Gobi desert region,it is more reasonable to select other forms of transmission tower structure.So a new type of transmission tower structure was adopted,namely Double Column Suspended Guyed Tower(DCSGT), which has characteristics of low construction cost,convenient construction,short time building, less steel etc; but the DCSGT are deficiencies that large flexibility,quality light, just small, big slenderness ratio even reached hundreds. Selecting this type of transmission tower structure because the xinjiang area has advantageous of, flat terrains, low cost area, which makes DCSGT economic advantage more prominent. However, daily average wind speed of Gobi desert region of xinjiang is larger, the maximum wind speed can reach 35 m/s,the under wind load, this tower structure is prone to a lot of swing,deformation and stress of some components would exceed the limit value,it is important to research the dynamic reliability index and the wind-induced response of DCSGT under wind load. According to the ansys platform accordance with the numerical simulation analysis,the paper researchs the wind-induced response of DCSGT under wind load and solve the dynamic reliability index of transmission tower line system of DCSGT by introducing the moment method, the main research work:①this paper has established joint distribution model of wind speed and wind direction by utilizing two-dimensional multiplication theorem. Through taking the daily maximum measured extreme value wind speed of kumul meteorological station during July 1, 1970 to August 31, 2013 as the data sample basis, The daily maximum extreme wind speed as a statistical analysis of sample points, drawing corresponding probability histogram of wind speed by utilizing 16 direction daily extreme maximum wind speed,fitting probability histogram of wind speed with four model probability distribution of wind speed, Sclecting fittest by comparing. To model probability distribution of wind speed of the 16 wind direction to achieve unification, which establish the angle of wind speed conditional probability model distribution of unified expression with parameter values of 16 wind speed probability model distribution; it realizes the continuous wind angle by using the normalized thought to establish probability model distribution of continuous wind angle.Obtaining successive type joint distribution model of wind speed and wind direction by utilizing the angle of wind speed conditional probability model distribution of unified expression combination with probability model distribution of continuous wind angle.②Analysis parameters(wind speed, wind direction, cross-rope sag-to-span ratio) changing leads to the wind-induced response of DCSGT changing. The three key structural parameters such as wind speed, wind direction, cross-rope sag-to-span ratio are studied,and their influences to the stability and safety of DCSGT.the paper use analysis method of time domain, taking different wind speed, wind direction and cross-rope sag-to-span ratio, and their influences to the three wind-induced vibration responses such as guy tension, the counter-acting force of mast support, and the along-wind displacement of the mast top.③Calculating the dynamic reliability index of guy tensionand and the along-wind displacement of the mast top under the wind load. Firstly, determining the failure mode of transmission tower line system of DCSGT,namely, as long as one of four guys fracturing or a displacement of tower top exceeding the maximum limit would impact normal work and even the whole structural system collapsing of DCSGT. Secondly, the performance function of the two failure mode has been established by utilizing the equivalent extreme value event.Threely, The point estimation is used to sclect space point of wind speed and wind direction,The first four-order moments method have been calculated the reliability index of guy tensionand and the along-wind displacement of the mast top under the wind load, to provide theoretical support of researching of DCSGT under wind load.