基于LS-DYNA和BP神經(jīng)網(wǎng)絡(luò)的修枝機(jī)跌落沖擊響應(yīng)研究
發(fā)布時(shí)間：2018-08-13 08:38
【摘要】：劇烈地沖擊碰撞使得很多機(jī)電類(lèi)產(chǎn)品在其使用壽命內(nèi)呈現(xiàn)失效的狀態(tài)。跌落沖擊所引發(fā)的毀傷也是園林修枝機(jī)的主要失效形式。當(dāng)前,電動(dòng)園林修枝工具產(chǎn)品的設(shè)計(jì)開(kāi)發(fā)一般遵從“產(chǎn)品原始設(shè)計(jì)-制造樣機(jī)-跌落試驗(yàn)-產(chǎn)品優(yōu)化設(shè)計(jì)”的傳統(tǒng)模式,這會(huì)耗費(fèi)大量的人力物力成本,已越來(lái)越不適合小機(jī)電,特別是產(chǎn)品個(gè)性化、結(jié)構(gòu)復(fù)雜的電動(dòng)園林修枝器具的市場(chǎng)要求。因此,研究經(jīng)濟(jì)實(shí)用且準(zhǔn)確高效的修枝機(jī)產(chǎn)品設(shè)計(jì)開(kāi)發(fā)模式,建立預(yù)測(cè)修枝機(jī)抗沖擊性能的新方法和設(shè)計(jì)合理的緩沖防護(hù)復(fù)合材料結(jié)構(gòu)成為亟需解決的熱點(diǎn)問(wèn)題。本文以寧波市產(chǎn)業(yè)技術(shù)創(chuàng)新重大專(zhuān)項(xiàng)(2015B11031)——“高效長(zhǎng)壽命低噪音刀片切割系統(tǒng)的研發(fā)及產(chǎn)業(yè)化應(yīng)用”和山西省山西省自然科學(xué)基金(201601D102035)——“泡沫鋁-聚氨酯復(fù)合結(jié)構(gòu)緩沖吸能特性及機(jī)理研究”為支撐,對(duì)某型號(hào)園林修枝機(jī)的跌落沖擊響應(yīng)開(kāi)展研究。本文從跌落沖擊理論及動(dòng)力學(xué)分析方法,園林修枝機(jī)跌落仿真與跌落試驗(yàn),修枝機(jī)結(jié)構(gòu)優(yōu)化設(shè)計(jì),BP神經(jīng)網(wǎng)絡(luò)預(yù)測(cè)模型建立和緩沖防護(hù)復(fù)合材料結(jié)構(gòu)設(shè)計(jì)等幾個(gè)方面進(jìn)行了深度探究。針對(duì)內(nèi)部結(jié)構(gòu)復(fù)雜的園林修枝機(jī)在跌落沖擊動(dòng)態(tài)過(guò)程中存在的不確定性,運(yùn)用Hypermesh和DYNA-ANSYS/LS聯(lián)合仿真技術(shù),對(duì)修枝機(jī)在水平跌落和豎直側(cè)向跌落兩種極限工況下的跌落過(guò)程進(jìn)行有限元仿真分析。然后在同樣的工況下,對(duì)修枝機(jī)進(jìn)行現(xiàn)場(chǎng)跌落試驗(yàn)。對(duì)比分析園林修枝機(jī)跌落仿真和跌落試驗(yàn)的結(jié)果,尋找到園林修枝機(jī)受到跌落沖擊后影響修枝機(jī)使用壽命的易損部件。然后在Hypermesh中對(duì)園林修枝機(jī)發(fā)生跌落沖擊后的易損部件進(jìn)行結(jié)構(gòu)優(yōu)化設(shè)計(jì),并通過(guò)有限元仿真驗(yàn)證改進(jìn)結(jié)構(gòu)是否符合要求。利用跌落仿真和跌落試驗(yàn)相結(jié)合的方法可更好地探究修枝機(jī)在發(fā)生跌落時(shí)的沖擊應(yīng)力響應(yīng)規(guī)律,為其結(jié)構(gòu)優(yōu)化提供科學(xué)依據(jù),從而設(shè)計(jì)了滿(mǎn)足使用需求的修枝機(jī)結(jié)構(gòu)。利用改進(jìn)前的符合修枝機(jī)跌落實(shí)際情況的修枝機(jī)跌落仿真參數(shù)化模型,得到修枝機(jī)在不同工況下跌落后主要部件(齒輪箱和旋轉(zhuǎn)管)的最大沖擊應(yīng)力樣本數(shù)據(jù)共20組,用于神經(jīng)網(wǎng)絡(luò)的訓(xùn)練與驗(yàn)證。通過(guò)建立跌落高度、跌落角度、地面材質(zhì)與主要部件最大沖擊應(yīng)力值之間的BP神經(jīng)網(wǎng)絡(luò)模型,運(yùn)用有限元仿真技術(shù)和神經(jīng)網(wǎng)絡(luò)相結(jié)合的方法,預(yù)測(cè)不同跌落沖擊狀態(tài)下園林修枝機(jī)的主要部件跌落沖擊最大應(yīng)力值,為園林修枝機(jī)耐撞性測(cè)試與可靠度評(píng)估提供新的參考,彌補(bǔ)跌落仿真時(shí)間過(guò)長(zhǎng)的缺憾。最后,結(jié)合沖擊試驗(yàn)和有限元仿真兩種方法,設(shè)計(jì)了性能更優(yōu)的緩沖防護(hù)復(fù)合材料結(jié)構(gòu),可將其廣泛地應(yīng)用于產(chǎn)品的運(yùn)輸包裝中,以避免修枝機(jī)等產(chǎn)品在運(yùn)輸、堆碼等過(guò)程所造成的跌落沖擊中發(fā)生破壞。
[Abstract]:Severe impact makes many mechanical and electrical products appear to be invalid in their service life. The damage caused by drop impact is also the main failure form of garden pruning machine. At present, the design and development of electric garden pruning tools generally follow the traditional mode of "product original design-manufacturing prototype-drop test-product optimization design", which will cost a lot of manpower and material resources. It has become more and more unsuitable for the market requirements of electric garden pruning apparatus, especially the individualized and complex structure of the products. Therefore, the research of economical, practical, accurate and efficient pruning machine product design and development model, the establishment of a new method to predict the impact resistance of the pruning machine and the design of reasonable cushioning and protective composite structure have become the hot issues that need to be solved. In this paper, Ningbo Industrial Technology Innovation Project (2015B11031)-"Research and Development of High efficiency and long Life low noise cutting system and its industrialization Application" and Shanxi Natural Science Foundation (201601D102035)-"Foamed Aluminium-Polyurethane Composite" Study on the Energy absorption characteristics and Mechanism of structure cushioning The drop impact response of a garden pruning machine was studied. The drop impact theory and dynamic analysis method, drop simulation and drop test of garden pruning machine are introduced in this paper. The structure optimization design of pruning machine and the establishment of BP neural network prediction model and the structural design of cushioning and protecting composite materials were studied in depth. In view of the uncertainty existing in the dynamic process of dropping impact of garden pruning machine with complex internal structure, the joint simulation technology of Hypermesh and DYNA-ANSYS/LS is used. The drop process of the pruning machine under the two limiting conditions of horizontal drop and vertical lateral drop was simulated and analyzed by finite element method. Then under the same working condition, the field drop test of the pruning machine is carried out. The results of drop simulation and drop test of garden pruning machine were compared and the vulnerable parts of garden pruning machine which affected the service life of garden pruning machine were found. Then the structural optimization design of the vulnerable parts of the garden pruning machine after falling impact is carried out in Hypermesh, and the finite element simulation is used to verify whether the improved structure meets the requirements. By combining drop simulation and drop test, the response law of impact stress of pruning machine can be better explored, which provides scientific basis for structural optimization, and thus designs the pruning machine structure that meets the needs of application. By using the parameterized model of the pruning machine drop which accords with the actual situation of the pruning machine before the improvement, the maximum impact stress sample data of the main parts (gearbox and rotary tube) of the pruning machine after dropping under different working conditions are obtained in 20 groups. It is used for training and verification of neural network. By establishing the BP neural network model between drop height, drop angle, ground material and the maximum impact stress of main components, the method of combining finite element simulation technology with neural network is used. The maximum stress value of the main parts of the garden pruning machine under different drop impact conditions is predicted, which provides a new reference for the crashworthiness test and reliability evaluation of the garden pruning machine, and makes up for the drawback of the falling simulation time. Finally, combined with impact test and finite element simulation, a better cushioning and protective composite structure is designed, which can be widely used in the transportation packaging of products, so as to avoid the transportation of pruning machines and other products. The damage occurred in the drop impact caused by the stacking process.
【學(xué)位授予單位】：中北大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TU986.32
[Abstract]:Severe impact makes many mechanical and electrical products appear to be invalid in their service life. The damage caused by drop impact is also the main failure form of garden pruning machine. At present, the design and development of electric garden pruning tools generally follow the traditional mode of "product original design-manufacturing prototype-drop test-product optimization design", which will cost a lot of manpower and material resources. It has become more and more unsuitable for the market requirements of electric garden pruning apparatus, especially the individualized and complex structure of the products. Therefore, the research of economical, practical, accurate and efficient pruning machine product design and development model, the establishment of a new method to predict the impact resistance of the pruning machine and the design of reasonable cushioning and protective composite structure have become the hot issues that need to be solved. In this paper, Ningbo Industrial Technology Innovation Project (2015B11031)-"Research and Development of High efficiency and long Life low noise cutting system and its industrialization Application" and Shanxi Natural Science Foundation (201601D102035)-"Foamed Aluminium-Polyurethane Composite" Study on the Energy absorption characteristics and Mechanism of structure cushioning The drop impact response of a garden pruning machine was studied. The drop impact theory and dynamic analysis method, drop simulation and drop test of garden pruning machine are introduced in this paper. The structure optimization design of pruning machine and the establishment of BP neural network prediction model and the structural design of cushioning and protecting composite materials were studied in depth. In view of the uncertainty existing in the dynamic process of dropping impact of garden pruning machine with complex internal structure, the joint simulation technology of Hypermesh and DYNA-ANSYS/LS is used. The drop process of the pruning machine under the two limiting conditions of horizontal drop and vertical lateral drop was simulated and analyzed by finite element method. Then under the same working condition, the field drop test of the pruning machine is carried out. The results of drop simulation and drop test of garden pruning machine were compared and the vulnerable parts of garden pruning machine which affected the service life of garden pruning machine were found. Then the structural optimization design of the vulnerable parts of the garden pruning machine after falling impact is carried out in Hypermesh, and the finite element simulation is used to verify whether the improved structure meets the requirements. By combining drop simulation and drop test, the response law of impact stress of pruning machine can be better explored, which provides scientific basis for structural optimization, and thus designs the pruning machine structure that meets the needs of application. By using the parameterized model of the pruning machine drop which accords with the actual situation of the pruning machine before the improvement, the maximum impact stress sample data of the main parts (gearbox and rotary tube) of the pruning machine after dropping under different working conditions are obtained in 20 groups. It is used for training and verification of neural network. By establishing the BP neural network model between drop height, drop angle, ground material and the maximum impact stress of main components, the method of combining finite element simulation technology with neural network is used. The maximum stress value of the main parts of the garden pruning machine under different drop impact conditions is predicted, which provides a new reference for the crashworthiness test and reliability evaluation of the garden pruning machine, and makes up for the drawback of the falling simulation time. Finally, combined with impact test and finite element simulation, a better cushioning and protective composite structure is designed, which can be widely used in the transportation packaging of products, so as to avoid the transportation of pruning machines and other products. The damage occurred in the drop impact caused by the stacking process.
【學(xué)位授予單位】：中北大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TU986.32
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