An Investigation On The Fatigue Design And Reinforcing Method Of Heavy Duty Steel Crane Beam

With the requirements of the national economy growing, equipment and production density in the workshop of each enterprise are growing. The frequency of crane’s use is increasing, the existence in actual works is difference from crane beam in design, many parts of them unbearable heavy duty burden, and fatigued to damage, and even cracking.This paper based on the actual working condition of the crane, checking design parameters of current "code for design of steel structures" by the stress test results in the site. For the crane which has fatigue failure in practical engineering, through checking the design result and record to modify the design parameters from a computational perspective, make the damaged steel crane beam reinforcement scheme, to ensure safety in production.First of all, introduce the types of crane girder crane beam, and the reasons of the fatigue failure generating. The analysis shows that, without considering the many unfavorable factors, resulting in crane beam design is not consistent with the actual work.Secondly, as an example, to study the fatigue design in the metallurgical crane girder, based on the statistical results of stress testing data, calculation of the heavy duty soft hook crane under equivalent coefficient of load effect should be0.9-1.1greater than0.8, which is the current standard (code for design of steel structures2003Edition).The actual engineering design should be consider in the future.Thirdly, the stresses mostly calculated by rain flow now, the counting model adopt the closed model totally. Before counting the prior stress time history of length and maximum and minimum stresses should be cleared according the position of the size of stress to adjust the connection time history, and then calculating, so it’s take more time and low efficiency. This paper introduced the model of rain flow real-time counting method. It count directly of the stress of peak and valley power in the stress calculation of crane beam, so this method lead to efficiencies.Comparing these two count models can be found, the closed model and real-time calculation model of stress values are the same, the latter of which saves20s time.Finally, the method of the crane beam repair and reinforcement scheme is described. As an example, make reinforcement of crack crane beam based on the actual damaged and field application. The actual stress test results show that, the equivalent stress range is reduced by27%, and so it’s a good application effect.