LITERATURE REVIEW In this project has two variables to control the process. There are vibration and green composite structure. Reading previous research and some journal have been done to have the knowledge and guidelines in order to commence this project. 1.1 Vibration Is a measurement of periodic or random process of an oscillations occur about to an equilibrium point. Vibration can be desirable and undesirable (Chakravorty et al., 1998). Mostly in many cases, vibration called undesirable because present of energy waste and unwanted sound is created. Vibration can be categorized into two types, that is free and forced vibration. Free vibration occurs when the system is set off with an initial input then allowed to vibrate freely and forced vibration is when a time-varying disturbance is applied to the system (Chakravorty et al., 1998). Figure 2. 1 : Type of vibration 1.1.1 Forced Vibration Occurs when the time varying disturbance such as load, displacement or velocity is added into a mechanical system (Chakravorty et al., 1998). The disturbance can be a steady-state input, random input, transient input or periodic. The periodic input can be a harmonic or a non-harmonic disturbance. For linear systems, harmonic input is a same amount of the frequency of the applied excitation or motion response with magnitude that depend on the actual mechanical system. 1.1.2 Vibration Testing Vibration testing is converting the function of force into a structure, usually with some of