二十六年前H. F. Tiersten教授在美國大學首度開創「電磁力學」課程。筆者受益匪淺。後來其他有關壓電與磁致伸縮的論文陸續地發表,推動了一門嶄新的有關電磁彈性力學的研究。這些研究更廣泛地被納入「高科技」領域裡的實務應用。本文將簡述本主題最近的發展情形。同時論述其基本數學,以供解說電、磁、熱對連續體,包括半導體,引起之物理現象。
對物體,電磁場是以Maxwell方程式來規範。而連續體力學要求作用於連續體的機械力、電磁力、與熱力等必需滿足大自然的三個守恒定律。其實,使用變分法,我們可以從能量守恒定律得到所有規範物理的數學關係式。這包括:「連續」、運動、熱傳、電磁等方程式,與有關的邊界條件。
電磁熱彈性力學是一門對學界具有挑戰性的學門。尤其它在「高科技」電子裝置的創新與研究、發展,將扮演得重要的角色。值得國內産學界的重視。筆者將陸續整合發表相關論文,以資抛磚引玉。
'Electro-Magnetic Mechanics' given as a graduate course by H. F. Tiersten and related publications on piezoelectricity and magnetostriction by others offered an open new field for research in Electro-magneto-thermal Elasticity, and particularly in the ”hi-tech” applications. It is the intent of this paper to review briefly the current state-of-the-art in the development of this subject and to discuss the basic mathematics for the discription of the physics of interaction between the electromagnetic field and/or temperature field and the deformable continua, including the semiconductor.
The electromagnetic fields are governed by the Maxwell's equation, while the mechanics of continua requires that the three fundamental conservation laws be met, including the action of the mechanical force, electric, magnetic, and thermal fields. In fact, all the governing equations of physics including equations of continuity, of motion, of heat conduction, Maxwell's relations, and the boundary conditions will result from the energy equation, using the variational method.
This still is an open field of study which challenges the academia, particularly in the development of ”hi-tech” devices for practical applications.