文档介绍：Examples FEA & ANSYS 1 Dimension MOHD SHIRAZ ARIS Department of Mechanical Engineering Universiti Teknologi Petronas FEA ? Basic steps in FEM a) Preprocessing b) Solution c) Post processing ? Consider heat transfer across posite wall, Example Solution ? Discretize the solution domain into finite elements ? Assume a solution From an energy balance, q = -kA dT / dx (conduction) q = hA (Ts - Tf ) (convection) 1 234 5 1 234 ? Develop equations for an element The heat transfer rates and temperature at the nodes are related by, q i = kA/l ( T i-T i +1) conduction q i = hA (T i-T i +1) convection ? Elemental description can be expressed in a matrix from, q i = kA/l 1 -1 T i q i +1 -1 1 T i +1 [K] = kA/l 1 -1 q = K T -1 1 ? Assembly to represent the entire problem Applying the elemental description for all elements K (e)= A U -U -U U K (1G) = A U -U 0 0 0 T 1 -U U 0 0 `0 T 2 0 0 0 0 0 T 3 0 0 0 0 0 T 4 0 0 0 0 0 T 5 ? Combining all elements: K (G)= K (1G) + K (2G) + K (3G) + K (4G) K (G) = A U 1 -U 1 0 0 0 T 1 -U 1 U 1 + U 2 -U 2 0 0T 2 0 -U 2 -U 2 + U 3 - U 3 0 T 3 0 0 - U 3U 3 +U 4 - U 4T 4 0 0 0 -U 4U 4T 5 ? Applying BCs and thermal loads: K (G) = A 1/