In the present finite element model an efficient stiffener element is proposed, which is compatible to degenerated shell element. Its combination with the shell element has given a unique tool for analyzing composite stiffened shells of wide variety. The analysis tool is equipped in such a way that it can be used to solve vibration, buckling and dynamic instability for a wide range of problems. The problem of laminated composite stiffened shell panels with uniform in-plane loading is analyzed. Four types of panel geometry are considered. The problem of isotropic stiffened panels is also taken in the present investigation. All the above mentioned analysis for laminated composite stiffened shell panels with non-uniform in-plane loading is done. Four types of different loading configurations are taken. This will help to enhance the understanding regarding the behavior of the structure subjected to dynamic load and it will definitely help a designer. The effect of cutouts are also studied. A number of new results are presented taking parameters into aspect, which will help the future researchers in this field for further investigation.