摘 要

本研究以平面應力假設並配合有限元素分析程式ANSYS 5.7版，針對裂岩機劈裂桿之性能，以不同的加載速率及楔型角度來進行數值模擬分析。此外，於實驗室進行小型劈裂模擬試驗，以五種不同之加載速率（5，15，25，35，45 ㎜/min），對兩組不同尺寸之試體（C組試體：0.4×0.4×0.09 m3，D組試體：0.32×0.68×0.09 m3），進行劈裂試驗；並以高速攝影機拍攝，藉以觀察裂縫開裂之過程。
在程式模擬方面，固定加載速率且變化大小不同之楔型角度，由最大張力處（A點）之應力值顯示，當楔型角愈大，將產生更大之側向徑向力。另外，分析尺寸效應問題，當劈裂路徑愈長，所得到之應力值愈小；但模擬變化不同之加載速率，以試體在同一長度（L），變化寬度（H）之作用下，1/4幾何形狀之X軸邊界上各點之應力值，無太大之變化。
實驗中，因試體尺寸及高速攝影機本身之限制，所以選擇1000張/秒）之拍攝速度，來擷取劈裂過程；且在10公分之尺標內，裂縫通過不到0.001s，故推估水泥砂漿試體裂縫傳播速率大於100 m/s。此外，以不連續面粗糙度（JRC值）之十個標準之粗糙剖面來量測破裂面粗糙度，其JRC值介於4到8之間；由JRC值之分佈顯示，當加載速率愈快，試體破裂面粗糙度之JRC值有愈大之趨勢。

關鍵字：有限元素分析程式ANSYS、加載速率、楔型角、劈裂試驗

Abstract
This study is performing data simulating analysis regarding the capability of Splitter’s thrust rod with different loading rates and wedge angles assuming plane stress in combination with finite element analysis program ANSYS 5.7. Besides, a few minor splitting simulating tests has been run in the laboratory using two different sizes of samples (sample C：0.4×0.4×0.09 m3，sample D：0.32×0.68×0.09 m3 ) with 5 sets of loading rates (5，15，25，35，45 ㎜/min) ; meanwhile, observing the progress of crack’s fracturing by high-speed video system.
In the program’s simulation at fixed loading rate with diverse wedge angles, the stress at the point (point A) with highest tension shows that the higher wedge angle result in a higher lateral radial stress. Furthermore, analyzing the dimension effects displays that the longer the splitting path is, the smaller the stress will be. However, when we simulate diverse loading rates, the stress values of every point remains less differential in the margin of x-coordinate of quadrant with same length (L) and diverse width (W) samples.
During the experiments, owing to the limit of sample’s size and high-speed video camera, we chose video speed of 1000 sheets per second to capture the splitting progress. In a 10cm measure, the crack will pass through less than 0.001s. So, we presume the transmitting speed of cracking cement-martar sample is more than 100 m/s. Furthermore, evaluate the roughness of crack plane by 10 standard rough profiles of Joint roughness coefficient (JRC), the JRC of samples are between 4~8. The distribution of JRC shows that the faster of loading rate goes, the tendency to higher value of JRC is.

Keyword:finite element analysis program ANSYS,loading rate,wedge angle,splitting

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