起重機(jī)結(jié)構(gòu)框架的優(yōu)化設(shè)計(jì)

　　摘要

　　為了找到能夠容易地安裝在常規(guī)農(nóng)用車輛上以及從常規(guī)農(nóng)用車輛移除的多用途起重裝置的最具成本效益的設(shè)計(jì),在支撐裝置的主框架上執(zhí)行包括材料和制造費(fèi)用兩者的成本優(yōu)化。優(yōu)化受到局部和全局屈曲和疲勞狀況的限制。將Snyman的基于梯度的LFOPC優(yōu)化算法應(yīng)用于連續(xù)優(yōu)化問(wèn)題,導(dǎo)致經(jīng)濟(jì)地確定明確的連續(xù)解,然后將其用作離散可用輪廊集合內(nèi)的鄰域搜索的起點(diǎn),以獲得離散最佳。對(duì)于不同的鋼種以及與不同國(guó)家的制造和材料成本相關(guān)的最佳進(jìn)一步調(diào)查。還研究了優(yōu)化目標(biāo)函數(shù)的公式變化的影響。結(jié)果表明,通過(guò)優(yōu)化可以獲得相當(dāng)大的成本效益,即在不同國(guó)家進(jìn)行成本核算不一定導(dǎo)致相同的最具成本效益的設(shè)計(jì),并且準(zhǔn)確地表達(dá)目標(biāo)函數(shù)(即現(xiàn)實(shí)的數(shù)學(xué)建模)對(duì)于獲得最大的收益預(yù)期的設(shè)計(jì)最佳。

　　Optimal design of a hoist structure frame

　　Abstract

　　In an attempt to find the most cost effective design of a multipurpose hoisting device that can be easily mounted on and removed from a regular farm vehicle, cost optimisation including both material and manufacturing expenditure, is performed on the main frame supporting the device. The optimisation is constrained by local and global buckling and fatigue conditions. Implementation of Snyman's gradientbased LFOPC optimisation algorithm to the continuous optimisation problem, results in the economic determination of an unambiguous continuous solution, which is then utilised as the starting point for a neighbourhood search within the discrete set of profiles available, to attain the discrete optimum. This optimum is further investigated for a different steel grade and for the manufacturing and material cost pertaining to different countries. The effect of variations in the formulation of the objective function for optimisation is also investigated. The results indicate that considerable cost benefits can be obtained by optimisation, that costing in different countries do not necessarily result in the same most cost effective design, and that accurate formulation of the objective function, i.e. realistic mathematical modelling, is of utmost importance in obtaining the intended design optimum. O 2003 Elsevier Inc. All rights reserved.