枸杞子 가지의 振動 特性 = Vibration Characteristics of Boxthorn(Lycium chinense Mill) Branch

다국어 초록 (Multilingual Abstract)

Modulus of elasticity, modulus of rigidity, damping ratio, and natural frequency of three varieties of boxthorn (Lycium chinense Mill) (Cheongyang #2, Cheongyang gugija, and Cheongyang native) branches were analyzed. Samples were obtained at Chongyang Boxthorn Experiment Station, Chungnam, Korea. Modulus of elasticity and modulus of rigidity of the boxthorn branch was determined using standard formulation after simple beam bending test and torsion test, respectively, using an Universal Testing Machine (UTM) equipped with self designed and constructed jigs. Damping ratio and natural frequency of the branch were determined after vibration test using accelerometer and PC equipped with A/D converter and software associated with vibration test.
Followings are results obtained from this research.
1. The modulus of elastic generally decreased as the diameter of the boxthorn branch increased in overall varieties and branch types combined and there was a good correlation (corr □ -0.81) between the elastic modulus and branch diameter. The range of the elastic modulus was 2.01xI0^9 ~ 4.97x10^9 N/m² with the range of the diameter of the boxthorn branch of 2.03~11.66 mm. The average elastic modulus of the total of 73 sample was 2.39x10^9N/m² with the average diameter of 4.76mm.
2. The torsional modulus of rigidity showed no significant difference in overall associated with the diameter of the boxthorn branch and the average modulus of rigidity was 6.53x10^8 N/m² in the total number of 88 samples of all varieties and branch types combined.
3. The overall range of the damping ratio of all varieties of the boxthorn branch combined was 0.014 ~ 0.087 and the internal damping results showed a high variability. The results, however, indicated that the boxthorn branch was a lightly damped structure.
4. The natural frequency of the boxthorn branch increased as the diameter of the boxthorn branch increased and there was a good correlation (corr = 0.82) between the natural frequency and the branch diameter. The range of the natural frequency was around 89 ~ 363 rad/s in overall varieties branch types combined.

목차 (Table of Contents)

• 목차
• LIST OF TABLES = iii
• LIST OF FIGURES = iv
• I. 서론 = 1
• II. 문헌개요 = 3
• III. 재료 및 방법 = 6
• 가. 공시재료 = 6
• 나. 실험장치 및 방법 = 6
• IV. 결과 및 분석 = 14
• 가. 탄성계수 = 14
• 나. 강성계수 = 18
• 다. 감쇠비 = 21
• 라. 자유진동수 = 23
• 마. 함수율 = 24
• V. 요약 및 결론 = 25
• ABSTRACT = 26
• 참고문헌 = 28
• APPENDICES = 30