| 摘要: | 本論文旨在探討探空八號火箭之酬載回收艙結構設計，並透過分析與實驗驗證設計之可行性。探空八號回收試驗任務主要延續探空六號火箭酬載回收艙回收計畫，並增加新的功能與任務：除增加三頻天線(UHF、GPS、S-Band天線)信號通訊功能與天線氣柱信號通訊功能，以提高回收機率外，也於艙體內增加冷流噴射酬載。冷流噴射試驗係利用回收艙在火箭回程時於高空100 km與火箭脫離後，以噴射壓縮氮氣的方式，進行回收艙姿態控制等相關試驗，同時並進行姿態量測與收集數據。與探六任務相較，本次探空任務之回收艙酬載重量增加，整體比重超過了海水密度，故本次任務除新增上述功能與任務，亦增加浮球裝置，使回收艙落海後得以在海面上漂浮並發出求救訊號，等待搜救任務。 探八回收艙機械設計重點包括，酬載與回收艙艙體構之結合設計、降落傘艙蓋與密封艙體脫離之機構設計、內部酬載避振設計、三頻天線窗戶結構設計、除錯與電源窗戶結構設計，浮球充氣與固定機構設計、冷流噴射艙設計等重要設計。因應本次飛試任務需要，其中部份設計與探六設計有所不同，如在避振結構設計上，採用中空圓錐形矽膠避振墊，以給定預壓縮的方式將矽膠避振墊安裝於避振座，使結構達到三軸減振的成效。求援天線則採氣柱方式設計，在氣柱上黏佈有三條軟質天線達成通訊功能，氣柱並與浮球設計為一體，當浮球開始充氣時，天線氣柱連帶充氣，將氣柱上的天線向上撐起，使天線功能可以順利運作。冷流噴射艙設計重點包含艙內元件固定與空間配置元件(包含壓縮氮氣瓶、爆通閥、調壓閥、調速閥與噴嘴)、回收艙壁與冷流噴射噴嘴結合設計。 本論文並利用Solidworks內建分析軟體 COSMOSWorks進行零件靜態力學分析，來驗證回收艙設計是否能夠達成任務需求，經由模擬分析後，由分析結果得知，回收艙各部主要受力結構皆能承受任務執行時所受的外部負載。 同時亦利用單軸振動機進行回收艙內部酬載框架的避振測試，以不同壓縮率、厚度與硬度之避振墊來進行實驗、從實驗結果找出避振效果最佳之矽膠避振墊，經由對各種參數之矽膠避振軟墊測試，得知厚度4mm、蕭式硬度A 70°之矽膠軟墊在壓縮量為壓縮10％時，能有效降低電路框底座在振動時所產生之振動能量。 探八回收艙目前已完成回收艙整體設計與部分艙體加工包含降落傘艙、密封艙、冷流噴射艙與抗熱盾，回收艙後續會進行中科院訂定之環境試驗以檢驗各部分功能是否達到設計需求，確保回收艙在任務中能在類似的環境之下運作。 The purpose of this thesis is to demonstrate the design approach for the mechanical structure of reentry capsule for Sounding Rocket VIII Mission (Abbreviated as SR08) in Taiwan, and to verify the feasibility of the design numerically and experimentally. The major goal of Sounding Rocket VIII Mission is to continue the plan of the reentry capsule for Sounding Rocket VI Mission (Abbreviated as SR06) with additional new tasks. There are three new main tasks developed in this mission, i.e. a tri-band antenna (UHF, GPS, and S-Band) for the signal communication, a rescue antenna designed in a gas column, and a cold gas propulsion payload. The mission of the additional payload of cold gas propulsion will be conducted at the altitude about 100 km after the reentry capsule separated from the rocket. The nitrogen gas thruster will control the attitude of the reentry capsule. Simultaneously all the measurement data of the attitude and other sensors will be recorded, and some of them will be also broadcasted to the ground station by the tri-band antenna. In comparison with the SR06 Mission, the weight of the reentry capsule of SR08 is increased and the density is correspondingly larger then that of sea water. Consequently an additional gas balloon is essential for the reentry capsule that it is capable of floating on the sea water for rescue. The main points of structural design for reentry capsule include the connection between the payload and the capsule structure, a separation mechanism for parachute chamber, an anti-vibration mechanism for the payload, tri-band antenna widows, debug and power connection widows, a balloon and the corresponding inflation mechanism, a chamber for the cold gas propulsion system. In order to fulfill the mission requirements, some of the design are quiet different than the reentry capsule of the SR06 mission, such as anti-vibration mechanism where conical silicone cushion pads are utilized to reduce the vibration in three axes. Another design consideration is the antenna for rescue, that is pasted on a gas column. In order to simplify the design, the gas column and the balloon are integrated as a whole one, and the gas column will be inflated uprightly as the balloon inflating. The design for the chamber for cold gas propulsion system includes here the arrangement of components of the system, and the interface design between the nuzzles and chamber structure. An FEM software, COSMOSWorks, is utilized in the study to verify the structural design. The analysis results show that the main structures of the reentry capsule can support the external loads while in mission. A vibration experiment is also conducted on a vibration testing machine to verify the performance of of the developed anti-vibration mechanism. In the experiment, the cushion pads with different compression ratio, thickness and hardness are considered and compared for the performance of vibration reduction. From the experimental results it is found that the pad will be the best if the thickness is 4 mm, the hardness is Shore A 70° and the compression ratio is 10％. Up to now the design and manufacturing of the reentry capsule have been completed. The functions of the design must be validated by the further environment tests and field tests to ensure that the reentry capsule can be operated under the mission environment. |
