مهندسی عمران شریف (Aug 2020)
محاسبه ی بازگشتی مدول کشسانی لایههای روسازی به روش ترکیبی دیفرانسیل کوادرچر و الگوریتم بهینهسازی جستجوی هارمونی
Abstract
The evaluation of pavements being utilized using falling weight deflectometer (FWD) is one of the most important components of the pavement management system in many countries. The computation of pavement layer properties to estimate the remaining life of the pavement and also pavement maintenance has always been of interest to road pavement researchers and engineers. On the other hand, the back-calculation is widely used for the estimation of the pavement layer properties. In most back-calculation methods, the commercial software such as ABAQUS, ANSYS, etc., are used as numerical simulation engine. But it is difficult to integrate them with the optimization engine and consequently, they require the pre-generated artificial analytical data for search space. ubsequently, much computational time due to the large number of iterations is required. In this paper, the differential quadrature method (DQM) is employed to analyze the pavement. By combining this method with harmony search (HS) optimization algorithm, a computationally efficient model is developed for calculation of surface deflections so that it significantly reduces the overall computational time for back-calculation. As an application of the proposed hybrid differential quadrature method and harmony search (DQ-HS) optimization algorithm, a numerical example for back-calculation of elastic modulus of a three-layer pavement structures is presented. The results of this study with different populations show that this method can be used to calculate the elastic modulus of the layers in less than 20 iterations. To demonstrate the efficiency of the optimization algorithm for harmonic search and the convergence independence of optimal solutions, the problem with 10 populations and repetition of 20 is performed 10 times with a series of random numbers. The results indicate that the independence of the method of optimization from random values. Fast convergence, high precision and low computational cost are the advantages of this proposed method to estimate unknown parameters of a multilayer structure, including pavement structure.
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