The four sides support the shape curve of the rectangular plate and its orthogonality

elastic sheets;  Free vibration;  Orthogonality of the shape of the shape

The main vibration direction ordering method believes that the vibration waveform in the vibration curve of the plate is unique in the main vibration direction and not unique in the other direction, so the accurate vibration curve expression of the four-sided supporting rectangular plate is established. This mode shape curve can satisfy the vibration differential equation and all boundary conditions, and also has the orthogonality of the mode shape. The existence of mode orthogonality is proved by derivation, the physical meaning of the principal oscillation direction ordering method is clarified, and the correctness of the method is theoretically explained.