Fatigue life prediction of existing crane runway girders

Fatigue Fract Eng Mat Struct

Ren

et al. 2016

For remanufacturing truck cranes with the characteristic of single piece production, the coupling effect of multi‐physical fields and the correlation of multi‐defect modes are also faced in service. This causes that the safety of crane jib structures has great volatility and uncertainty and is difficult to be judged by fatigue test and damage test. To solve the above problems, an approach of fatigue remaining life evaluation based on random load spectrum is presented. By collecting operating cycle times corresponding to characteristic parameter values during the given time period, the small‐sample measured load spectrum is acquired. Six probability distribution models are used to fit the lifting weight sample in characteristic parameters and the optimal distribution model based on Akaike's information criterion (AIC) is obtained. With the Latin hypercube sampling (LHS) method, a random sample of lifting weight is determined within the fixed inspection cycle. In addition, combining with the rated lifting weight table of truck crane, the corresponding jib length and working range are confirmed. Through defining random values of character parameters and matched operating cycle times, a random load spectrum is gained, thus enabling the extension of measured load spectrum. Depending on the remanufacturing information database, the remanufacturing information of truck crane are retrieved to determine fatigue dangerous cross sections and critical points of jib structures. In order to reflect the variation of structure stress level, the equivalent cross sections of dangerous cross sections are constructed. The first principal stress–time history simulation model for critical points is established, and the rain‐flow counting technology is adopted to extract the two‐dimensional stress spectrum from simulation results. Using the Paris formula combined with the greatest risk principle, the fatigue residual life of jib structure is estimated. Furthermore, the fatigue remaining life evaluation system for jib structure of remanufacturing truck crane is developed for easier application of the proposed method. Finally, as an illustrative example, jib structures of ZLJ5551JQZ110V remanufacturing truck crane are provided to demonstrate the validity and feasibility of this method and system.

Section: Fatigue Residual Life Calculationmentioning

confidence: 99%

Section: Fatigue Remaining Life Of Jib Structure Under Remanufacturinmentioning

confidence: 99%

Fatigue remaining life estimation for remanufacturing truck crane Jib structure based on random load spectrum

Fatigue Fract Eng Mat Struct

Ren

et al. 2016

“…Huang presents the fatigue life prediction method on the basis of limited test combined with numerical calculation to calculate the fatigue life of larger components under tensile loads. The finite element model of crane rail is established by Ozden through recording the load spectrum of bridge crane under operational conditions to probe into the fatigue residual life of the rail. Wang and Cai develop the fatigue life prediction and reliability evaluation system of truss jib to perform the real‐time assessment of the integration of recording load, life calculation, and the security decisions.…”

Section: Introductionmentioning

confidence: 99%

Fatigue residual life estimation of jib structure based on improved v‐SVR algorithm obtaining equivalent load spectrum

Fatigue Fract Eng Mat Struct

2020

Fatigue tests of truck crane jib structure have great difficulty, long testing cycle, and high cost. Therefore, with the portfolio strategy for "collection, prediction, measurement and simulation" being introduced, an improved support vector regression (v-SVR) algorithm is proposed to predict the equivalent load spectrum based on the small measured load spectrum and the fatigue residual life evaluation model is built. First, the v-SVR algorithm corrected in kernel function, decision function, and parameter optimization is utilized to acquire the equivalent load spectrum. Second, the distribution of critical points is determined by the case-based reasoning technique. The simulation model of first main stress-time histories for critical points is established, and the twodimensional stress spectrum is obtained by the rain-flow counting method. Finally, the fatigue residual life of jib structure is estimated by the Forman formula. Taking ZLJ5551JQZ110V truck crane jib structure as an example, the effectiveness of the above method is validated.KEYWORDS equivalent load spectrum, fatigue residual life, improved v-SVR algorithm, jib structure

“…The fatigue residual life of track girder of crane running for 30 years is described in (Ávila G et al, 2017) and the results show that the fatigue failure is most likely to occur at the welded joint. Under the condition of load spectrum generated by crane historical operation record data, the fatigue residual life of the rail girder is given in (Caglayan O et al, 2010) by the standard static load test combined with the established finite element model. For the abnormal phenomenon of rail gnawing and rail breaking of 450t bridge crane, the finite element analysis method for the influence of the high-low dislocation of crane track on the track girder is proposed in (Zhiqiang L et al, 2017 ).…”

Section: Introductionmentioning

confidence: 99%

Fatigue residual life prediction of casting crane under track defect model

Xin

2018

JAMDSM

For the safety problems caused by abnormal changes of stress-time history at fatigue risk points of casting crane metal structure due to the vertical impact effect of track defects, the forecast method of fatigue residual life of casting crane under track defect model is proposed. Guided by the kinematics and dynamics theory, the kinematic-dynamic model of dynamic load resulted from crane travelling on defective track including the highlow dislocation and horizontal gap is established. The influence of track defects on the vertical impact effect of operation crane is analyzed. Furthermore, combining with the collection of technological process and usage of casting crane, the characteristic parameters needed in the process of stress spectrum acquisition are determined. The allowable stress method combined with finite element simulation is used to get the fatigue risk cross-sections and points of crane metal structure and the first principal stress-time histories of dangerous points are obtained. The double parameter stress spectrum of dangerous points is extracted by rain flow technology. Based on fracture mechanics and damage tolerance design, the fatigue residual life of dangerous points is estimated by Paris formula. Taking the 100/40t-28.5m casting crane as an example, the feasibility of the above model and method is verified.