• 대한기계학회논문집A
• /
• 제34권6호
• /
• pp.701-708
• /
• 2010

면외평면전단하중과 면내전기하중을 받는 직교이방성 압전재료에서 전기투과형 전파균열장을 해석하였다. 압전재료에서 전파하는 균열의 운동방정식이 유도되었으며 근접해법을 통하여 응력장과 변위장의 해를 얻었다. 압전상수 및 유전율 등이 균열선단의 응력장과 변위장에 미치는 영향을 명확히 나타내었다. 본 연구에서 유도된 응력장과 변위장을 사용하여 압전재료에서 전파하는 균열선단부근의 응력과 변위의 특성에 대하여 논의하였다.

• Steel and Composite Structures
• /
• 제33권4호
• /
• pp.509-523
• /
• 2019

In the present work, the buckling analysis of micro sandwich plate with an isotropic/orthotropic cores and piezoelectric/polymeric nanocomposite face sheets is studied. In this research, two cases for core of micro sandwich plate is considered that involve five isotropic Devineycell materials (H30, H45, H60, H100 and H200) and an orthotropic material also two cases for facesheets of micro sandwich plate is illustrated that include piezoelectric layers reinforced by carbon and boron-nitride nanotubes and polymeric matrix reinforced by carbon nanotubes under temperature-dependent and hydro material properties on the elastic foundations. The first order shear deformation theory (FSDT) is adopted to model micro sandwich plate and to apply size dependent effects from modified strain gradient theory. The governing equations are derived using the minimum total potential energy principle and then solved by analytical method. Also, the effects of different parameters such as size dependent, side ratio, volume fraction, various material properties for cores and facesheets and temperature and humidity changes on the dimensionless critical buckling load are investigated. It is shown from the results that the dimensionless critical buckling load for boron nitride nanotube is lower than that of for carbon nanotube. It is illustrated that the dimensionless critical buckling load for Devineycell H200 is highest and lowest for H30. Also, the obtained results for micro sandwich plate with piezoelectric facesheets reinforced by carbon nanotubes (case b) is higher than other states (cases a and c).The results of this research can be used in aircraft, automotive, shipbuilding industries and biomedicine.

• 대한기계학회논문집A
• /
• 제26권2호
• /
• pp.283-290
• /
• 2002

In this paper, we consider the dynamic electromechanical behavior of an eccentric Yoffe permeable crack in a piezoelectric ceramic strip sandwiched between two elastic orthotropic materials under the combined anti-plane mechanical shear and in-plane electrical loadings. Fourier transforms are used to reduce the problem to the solution of two pairs of dual integral equations, which are then expressed to a Fredholm integral equation of the second kind. The initial crack propagation orientation for PZT-5H piezoceramics is predicted by maximum energy release rate criterion.