Papers by Author: Li Xing Huo

Paper TitlePage

Authors: Li Xing Huo, Min Liu, You Feng Zhang, Fang Juan Qi
Abstract: To increase the accuracy of R-F method, it is necessary to solve the problems of the linear expansion of failure function and non-normal variables. In this paper, the improved FOSM method was applied to calculate the failure probability of welded pipes with cracks. The examples show that this method is simple, efficient and accurate for reliability safety assessment of welded pipes with cracks. It can save more time than the Monte Carlo method does, so that the improved FOSM method is recommended for general engineering reliability safety assessment of welded pipes with cracks.
561
Authors: Bo Lin He, Ying Xia Yu, Si Yong Lei, Li Xing Huo
Abstract: It is important for the design engineer to realize that scatter and variability of materials properties are inevitable and must be dealt with appropriately. On occasion, data must be subjected to statistical treatments and probabilities determined. The fracture toughness of pipe steel has great effect on the safety of welded pressure pipe. The fracture toughness test of circumferential welded joint was carried out in this paper for X65 pressure pipe steel. The fracture toughness experimental results were analyzed by using computer program developed by ourselves. The distribution of weld fracture toughness of X65 pressure pipe steel which may accord with normal distribution, lognormal distribution or weibull distribution can be determined by calculating the results only one time. The program, which plays an important role in structure reliability analysis, can be used to determine the probability statistic distribution of the mechanical properties. The calculated results indicate that the weld fracture toughness of the X65 pressure pipe steel can either accord with normal distribution, lognormal distribution or weibull distribution, but the optimum fitting distribution of the fracture toughness is weibull distribution.
346
Authors: Li Xing Huo, Y.I. Liu, You Feng Zhang, Hong Yang Jing
1327
Authors: Bo Lin He, Ying Xia Yu, Li Xing Huo, Yu Feng Zhang
Abstract: In this paper, the reliability of welded pressure pipe with circumferential surface crack was calculated by using three dimensional stochastic finite element method for A131 pipe steel. This method has overcome the shortcomings of conservative results in safety assessment with deterministic fracture mechanics method. The calculation of reliability was based on three dimensional elastic-plastic stochastic finite element programs which were developed by ourselves. The calculation results indicate that the external load has great effect on the reliability of the welded pipe. When the mean value of bending moment changes from 10000N.m to 20000N.m, the failure probability of the welded pipe will change from 3.3750×10-9 to 1.6794×10-1. When the mean value of moment is changed from10000N.m to 20000N.m, the failure probability of the welded pipe increases dramatically for the same circumferential crack opening angle, inner pressure and the crack depth. The method has put forward a new way for safety assessment of welded pipe with circumferential surface crack.
664
Authors: Bo Lin He, Ying Xia Yu, Li Xing Huo, Yu Feng Zhang
Abstract: The reliability of welded pressure pipe with circumferential surface crack was calculated by using 3-D stochastic finite element method. This method has overcome the shortcomings of conservative results in safety assessment with deterministic fracture mechanics method. The calculation of reliability was based on 3-D elastic-plastic stochastic finite element program which was developed by ourselves. The effects of variables such as bending moment, the inner pressure on the structure reliability were discussed. The calculation results indicate that the bending moment has great effect on the reliability of the welded pipe, and the inner pressure has little effect on the reliability of the welded pipe if the inner pressure is less than 10MPa. If the mean value of the inner pressure changed from 0.5MPa to 30MPa, the failure probability will changes from 10-6 to 10-2. The bending moment also has great effect on the reliability. When the mean value of moment is changed from10000 Nm to 15000 Nm, the failure probability of the welded pipe increases dramatically for the same inner pressure. Irrespective of the changing of moment, the pipe has higher reliability if the inner pressure is less than 6 MPa. The method has put forward a new way for safety assessment of welded pipe with circumferential surface crack.
2513
Authors: Fa Yong Jia, Li Xing Huo, Gang Chen, Qun Peng Zhong
Abstract: Fatigue strength of duplex stainless steel welded joints with longitudinal fillet welded guess and with longitudinal flat side guess welded on plate was evaluated by hot spot stress, hot spot stress S-N curves were produced and compared with normal stress S-N curves. The results show that the hot spot stress fatigue strength of the two kinds welded joints should be expressed by only single S-N curve while nominal stress S-N curves can only be regressed respectively. The test data are greatly above the S-N curves with slope m=3, recommended by IIW, which indicates that the slope m=3(IIW) has great safety factor in practical engineering application. But there is no appreciable difference in fatigue strength between duplex stainless steel and common structural steel with similar welded joints when fixed the test data to slope m=3.
779
Authors: Li Xing Huo, Dongpo Wang, You Feng Zhang, Jun Mei Chen
1315
Authors: J.D. Kang, Li Xing Huo, You Feng Zhang
41
Authors: Bo Lin He, Ying Xia Yu, Li Xing Huo, Yu Feng Zhang
Abstract: In this paper, the reliability of welded pressure pipe with circumferential surface crack was calculated by using three dimensional stochastic finite element method. This method has overcome the shortcomings of conservative results in safety assessment with deterministic fracture mechanics method. The calculation of reliability was based on three dimensional elastic-plastic stochastic finite element program which was developed by ourselves. The effects of variables such as fracture toughness, bending moment and the depth of the circumferential surface crack on the structure reliability were also discussed. The calculation results indicate that the crack depth has great effect on the reliability of the welded pipe. When the mean value of the crack depth is changed from 3mm to 7mm, the failure probability of the welded pipe will change from 10-8 to 10-2. The bending moment also has great effect on the reliability of the welded pipe. When the mean value of moment is changed from10000 N.m to 15000 N.m, the failure probability of the welded pipe increases dramatically for the same circumferential crack depth. Irrespective of the changing of moment, the pipe has higher reliability if the crack depth is less than 5mm(a/t<0.5, t is the thickness of the pipe). The method has put forward a new way for safety assessment of welded pipe with circumferential surface crack.
639
Showing 1 to 10 of 14 Paper Titles