本文選題：自同步振動機理 + 南極冰下環(huán)境��； 參考：《吉林大學》2017年博士論文

【摘要】：南極冰架下、冰下湖水體底部沉積物包含著重要的古氣候、古環(huán)境信息,可為研究南極冰架的進退歷史、冰架下海洋環(huán)流方式提供歷史尺度的觀測手段,同時也為極地環(huán)境下微生物生命形態(tài)的研究、原始生命形式的探索帶來新的契機。目前,南極冰下沉積物樣品的獲取主要依托于熱水鉆技術,取樣設備需要通過熱水鉆先導孔到達水體底層后,才能開展沉積物的取樣操作,特殊的工作場合對取樣器的選型、設計提出了一系列的技術挑戰(zhàn)。本文對南極冰下沉積物取樣技術特點進行分析,總結該領域存在的若干技術難題,綜合常規(guī)水下沉積物取樣器、南極冰下沉積物取樣器的研究現狀,提出自同步式冰下沉積物振動取樣器的設計方案。論文主要取得了以下研究成果:1、參照我國“863”項目“冰架熱水鉆機關鍵技術與系統開發(fā)”中的相關參數要求,完成了取樣器的整體結構設計。整體結構采用模塊化的設計方法,將取樣器拆解成防水壓力艙、振動器、取樣管部件以及彈簧減振器四個主要部件,按照相關邏輯順序對各部件逐個展開設計。其中,在振動器部件的設計中,引入雙質體振動系統自同步原理,設計了雙電機自同步式柱狀振動器,使取樣器的徑向結構尺寸大大縮小。最終確定取樣器的結構設計參數為:最大徑向尺寸270mm,整體長度4.3m,總質量203kg,取芯長度3m,取芯直徑94mm,總功率400W,。2.基于ANSYS Workbench模擬分析平臺,模擬壓力艙部件在2200m水體內振動狀態(tài)下的承載狀態(tài),分別建立壓力艙部件的結構靜力學、瞬態(tài)動力學有限元分析模型,觀察模型在靜載、靜-動載荷條件下的力學響應。在結構靜力分析模塊中對壓力艙模型施加靜態(tài)水壓載荷,得出結構承載條件下的受力危險區(qū)域,并結合分析結果對原始結構進行改進設計。在結構瞬態(tài)分析模塊中對改進后壓力艙模型同時加載水壓載荷、振動載荷,分別分析了壓力艙結構在水壓-縱向振動、水壓-水平振動兩種載荷作用下的力學響應,最終驗證了本文所設計的壓力艙結構在水壓、振動載荷聯合作用下耐壓性能。3.建立了冰下沉積物取樣模擬測試實驗臺,對取樣器的同步性能及取樣能力進行了測試。實驗結果表明:(1)取樣器在懸停、進尺過程中均能快速達到同步振動狀態(tài),振動頻率0-46.5Hz無級可調,加速度幅值為1.33g;(2)在使用模擬沉積物的物質組成與南極冰下沉積物相近的情況下,所設計取樣器能夠達到指定的3m進尺深度,并且所取沉積物樣品壓實率較低、水-沉積物交界面保存良好;(3)與依靠取樣器自身慣性的重力式貫入取樣相比,振動式取樣的貫入深度為重力式取樣的兩倍以上。4.所設計振動取樣器能夠實現豎直、水平、豎直-水平交替三種振動模式,利用模擬測試實驗臺,對三種模式下的進尺速率進行對比性實驗。實驗結果表明:振動模式的變更會對取樣器的進尺速率造成一定的影響。三種振動模式中,交替振動模式下取樣器的平均進尺速率最高,可達到77.8mm/s;水平、豎直振動模式下的平均進尺速率依次遞減,分別為71.17mm/s、54.9mm/s;三種模式下,取樣器均能夠在80s內完成3m以上的進尺深度。此外,取樣管進入沉積物后,適當的對振動模式進行變換,有助于提高取樣器的貫入能力。目前,我國正在加大投入南極熱水鉆系統的研究,中國南極熱水鉆探項目計劃明年在南極埃默里冰架實施熱水鉆探目標。本文所提出的自同步式冰下沉積物振動取樣器,針對“863”項目“冰架熱水鉆機關鍵技術與系統開發(fā)”進行設計。通過有限元模擬分析及實驗測試,初步驗證了取樣器結構設計、工作原理的可行性,為我國南極冰下沉積物取樣設備的研制提供了重要的技術支持。
[Abstract]:Under the Antarctic ice shelf, the bottom sediments of the subglacial lake water body contain important paleoclimate. The Paleoenvironment information can provide historical scale observation means for the study of the Antarctic ice shelf history, the ocean circulation under the ice shelf, and the research on the microbial life form under the polar environment. The exploration of the primitive life forms brings a new opportunity. Before, the acquisition of the subglacial sediments in Antarctica is mainly based on the hot water drilling technology. The sampling equipment needs to carry out the sampling operation of the sediment by the hot water drilling pilot hole to the bottom of the water body. A series of technical challenges are put forward for the selection of the sampler in special work situations. This paper takes the sampling technique of the subglacial sediments in the Antarctic. The characteristics are analyzed, and some technical problems in this field are summarized. The research status of the conventional underwater sediment sampler and the Antarctic subice sediment sampler are summarized. The design scheme of the self synchronous underwater sediment vibration sampler is proposed. The main results are as follows: 1, referring to the "863" project "ice shelf hot water rig" in China The integral structure design of the sampler is completed by the relevant parameters in the key technology and system development. The overall structure uses a modular design method to dismantle the sampler into a waterproof pressure chamber, vibrators, sampling tube parts and spring damper four main components, which are designed one by one according to the logical sequence. In the design of the vibrator components, the self synchronizing principle of dual mass vibration system is introduced, and a dual motor self synchronous cylindrical vibrator is designed to make the radial structure size of the sampler greatly reduced. Finally, the structure design parameters of the sampler are determined as the maximum radial size 270mm, the length of the whole body 4.3m, the total mass 203kg, the core length 3M, the core diameter. 94mm, total power 400W,.2. based on the ANSYS Workbench simulation analysis platform, simulate the bearing state of the pressure chamber components in the vibration state of the 2200m water body, establish the structural statics of the pressure compartment components, the transient dynamic finite element analysis model, observe the mechanical response of the model under static load, static and dynamic load conditions. In the block, the static water pressure load is applied to the model of the pressure chamber, and the dangerous area under the condition of structure loading is obtained, and the original structure is improved with the result of the analysis. In the structure transient analysis module, the water pressure load and the vibration load are loaded at the same time, and the hydraulic pressure longitudinal vibration of the pressure tank structure is analyzed. The mechanical response of the two kinds of loads under the action of two kinds of loads, such as motion, water pressure and horizontal vibration, finally proved that the pressure cabin structure under the combined action of water pressure and vibration load designed in this paper has set up an underwater sediment sampling simulation test bench to test the synchronizing performance and sampling ability of the sampler. The experimental results show that: (1) sampling (two) In the process of hovering, the synchronous vibration state can be achieved quickly, the vibration frequency 0-46.5Hz is stepless and the amplitude of the acceleration is 1.33g; (2) the designed sampler can reach the specified 3M depth and the compactness of the sediment sample under the condition that the material composition of the simulated sediments is similar to the Antarctic subglacial sediments. Lower, the water sediment interface is well preserved; (3) compared with the gravity penetration sampling which depends on the self inertia of the sampler, the vibratory sampling depth is two times more than the gravity sampling.4., and the vibration sampler can achieve the vertical, horizontal, vertical and horizontal alternation of three vibration modes, and use the simulated test bench for three kinds. The experimental results show that the change of the vibration mode will have a certain effect on the footage rate of the sampler. In the three vibration modes, the average footage rate of the sampler under the mode of alternating vibration is the highest, which can reach 77.8mm/s; the average footage rate in the vertical vibration mode decreases in turn, In the three modes, 71.17mm/s, 54.9mm/s, the sampler can complete the depth of more than 3m in the 80s. In addition, after the sampling tube enters the sediment, the proper transformation of the vibration mode is helpful to improve the penetration ability of the sampler. At present, China is increasing the research on the Antarctic hot water drilling system, China's Antarctic hot water drilling. The project plans to implement the hot water drilling target in the Antarctic Amery ice shelf next year. The self synchronous underwater sediment vibration sampler proposed in this paper is designed for the "863" project "key technology and system development of ice shelf hot water drill". Through the finite element simulation analysis and experimental test, the structure design of the sampler is preliminarily verified. The feasibility of the principle provides important technical support for the development of the sampling equipment for the Antarctic subglacial sediments in China.
【學位授予單位】：吉林大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：P343.6;P634.3

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