- 作者: 徐德修
- 作者服務機構: 國立成功大學土木系
- 中文摘要: 介紹現存結構破壞度之評估,結構之破壞以裂縫模擬之,所有裂縫均以旋轉彈簧取代以進行分析之工作,尋求具有不同裂縫狀況之結構與其自然振動頻率之關係,利用拉格朗奇式誘導具裂縫之懸臂梁之運動方程式,進而利用賈庫比法尋求其自然頻率;另以有限元素法假設適當的形狀函數尋求其運動方程式,兩組結果做一比較獲得模擬旋轉彈簧之彈簧係數,以便應用在任何平面桿件構架上,勁度矩陣及質量矩陣亦可以有限元素法求出據以尋求受損平面桿件構架之自然振動頻率。
- 英文摘要: The concept of damage assessment of existing structures is introduced. Damage of the structure ismodelled as cracks in the structure. All of the cracks are replaced by a simulated rotational spring. Rela-tionships between natural frequency and the cracked structures with different crack conditions are found.An equation of motion of the cracked cantilever beam is derived by Lagrange's equation. Natural fre-quency is then calculated by using Jacobi's method. An alternative equation of motion of the crackedcantilever beam is found by the finite element technique by assuming some proper shape functions. Thetwo results are compared to obtain the spring constant of the simulated rotational spring which is insertedat the cracked locations. The stiffness matrix and mass matrix for the cracked element can also be calculat-ed and the natural frequencies of any cracked plane frame structures are obtained accordingly.
- 中文關鍵字: natural frequency; damage assessment; cantilever beam; cracked plane frame
- 英文關鍵字: --