Vibration and Its Implications, Active and Passive Methods of Vibration Control - Coursework Example

Running Header: Vibration and Its Implications Student’s Name: Instructor’s Name: Course Code & Name: Date of Submission: Vibration and Its Implications Table of Contents Table of Contents 2 1.0 Introduction 3 2.0 Areas that vibration needs to be addressed 3 3.0 Methods of Vibration control 5 3.1 Active Methods of Vibration Control 5 3.2 Passive method of vibration control 6 4.0 Eliminating Vibration during Design 7 5.0 Conclusion 8 6.0 References 9 1.0 Introduction Vibration is the movement of the movement of a body, particle or a system of bodies periodically about an equilibrium position (Elias 2010, p .10). It is a movement that involves very high frequency or speed. This movement involves components that are interconnected together or have a link that join them. When vibration is taking place, these components are displaced from the equilibrium position at a different rate. Displacement of mechanical system from the equilibrium position makes the system to tend to return to its original position though the action of restoring forces. The momentum of the system and the operating force makes the system shift from the equilibrium position even with the effort of the restoring force to return the system to the equilibrium. This is what causes the system to move to and from the equilibrium position hence causing vibration. 2.0 Areas that vibration needs to be addressed In areas that are likely to cause undesirable results to the operation of the machine due vibration of the machines, then such situations vibrations issues of vibration should be addressed (Kostúr & Phan 1994, p. 18). Most forms of vibrations are undesirable therefore producing negative effects on the system within which they are operating. Vibration absorbs energy from the system, creates discomforts on the operating environment of the system, induces fatigue, increases bearing loads, causes added wear and produces increased energy losses and stress. As a result, in the design of the mechanical system effort is made to make sure that vibration is minimized to the lowest level possible. Areas where vibration creates discomfort in the operating environment of the machine or the system need to be addressed. In this case it is vivid predictions can be made that due to vibration of the machine, the machine would end up being destructive (Vestlel & Prisca 1974, p. 75). In some situations, the machine ends up producing components with defects. The machine may also be hoisted on a higher surface which means continuous vibration may cause it to fall down therefore destroying the entire machine. In other situations, the machine may injure persons who are operating it. There are areas where vibration causes fatigue to the machine itself or part of the system that is connected to the machine. Some parts of the machine may also end up weakening therefore requiring replacement. Furthermore, in areas that vibration occurs may become weak due to overheating of these areas leading to fatigue. Fatigue is the weakening of the materials that are under stress. In this case, continuous vibration cases certain component of the system to weaken and eventually fail to respond appropriately. To prevent this from happening, periodic checks on the nature of the system and how it is responding to different conditions should be regularly inspected. Extreme form of vibrations causes wearing and tearing of the component parts that are involved. When such a situation occurs, it may cause the whole machine to stop working awaiting the component to be acquired and replaced. Overall, the cost of maintenance in rotating, reciprocating and moving parts is majorly due to vibration. This vibration may cause undesirable losses that to the entire working system. As a result, there is a very high cost of maintenance that comes along in maintenance of the components that are destroyed due to oscillation. It is therefore important to ensure that vibration is managed within a safe level otherwise it would cause major losses. 3.0 Methods of Vibration control Vibration control is important in machines where vibration is desirable as well as situations where vibrations are undesirable. In machines where vibration is desirable, it is important to keep these vibrations at safe limits so that the vibrations produce the desirable result. Whenever the level of vibration exceeds a certain level, then control mechanism are used to return it to safe levels. In machines where vibration is undesirable, the aim is to make sure that these vibrations are fully eliminated. There are two major methods that are used to control vibration; Active method and the passive method (Elias 2010, p.11). 3.1 Active Methods of Vibration Control These are methods that lead to parametric and structural adjustments of the systems that are vibrating. To achieve this, additional source of energy are added to curb vibration at various points. When one of the operating points of the structure or the mechanical system is found to be having a lot of vibration, the various interconnected section of the system are adjusted in a way that they shall control this vibration (Elias 2010, p.11). The highest level of using active methods is to control the external power sources is through absorbing or supplying energy using determined control algorithm. Where the source of vibration is identified, a controller that is used to convert the energy that causes this vibration to other forms is used. A controller that converts physical values of pressure, force, acceleration, speed and movement is amplified and actuated into other forms such as pneumatic, hydraulic or electrical then connected to the device that actually causes vibrations. The role of the actuator in this case is to produce some form of force that compensates the forces that causes vibration. Moreover, it changes the parameters of the system in the active way. Why it is called active is because, the kind of modification required involves one to take active role of putting extra energy in order to reduce vibration. The active systems that are incorporated might produce some new form of force that is related to the variables that are assigned to the other system. Using active control is a problem of optimal control for the whole device. 3.2 Passive method of vibration control Passive methods of vibration involves the following Vibration damping Structural modification Parametric modification Protection of the vibration reason The protection of the vibration reasons involves eliminating the additional sources of energy or eliminating or decreasing the input forces and further isolating them from the external disturbances (Tirms & Chung 1984, p. 75). Mechanisms used in this case involves substitution of rolling bearings by slide ones, balancing decreasing the number of bodies which are colliding in the system among others. The parametric modifications are aimed at changing the stiffness or mass of the elements in use. Structural modifications on the other hand involve introduction of some more constrains to the system or removing of the already existing ones. This ensures that there is continuity in interrupting the structure that is vibrating through introduction of vibroisolators (Elias 2010, p.12). Vibroisolators are the intermediate elements that are put in the system with the aim of reducing the rate of vibration of between the linked parts. Damping is an additional important parameter that takes the secondary part or meaning in control in eliminating vibration. Damping refers to dissipation of the mechanical energy with the exchange of it with heat. Basically, the process causes reduction in the general efficiency of the devices or machines. In ideal situations, machines are required to run with zero damping value, so dumping mechanisms are used to ensure that the machine at least damps most of it. Damping is majorly used in situations where it is difficult to eliminate undesirable vibrations through parameter or constructional changes. Additional dumping involves using constructional materials that have required frictional joints, damping value or through use of additional dampers for example use of the hydraulic ones. 4.0 Eliminating Vibration during Design The design of a system that eliminates issues of vibration to the highest degree is something that is desirable in design engineering. Where parts are revolving and interconnected, it is difficult to fully eliminate vibration (Dealnt 2000, p. 918). However, it is possible to reduce this vibration to a level whose effects can be managed. The design specifications are the major determinants of the extent to which mechanically designed system would eliminate vibration. Before the final design is implemented, a model that clearly shows the behavior of the system should be analyzed and all the possible situations observed. Areas that are found to be having weaknesses or being affected by vibration should be addressed. If the mechanism to address the vibration is put in place during the design stage, it would reduce the overall running cost of the machine than when such an issue is addressed when the machine is implemented. Caution should also be taken to ensure that the vibration control devices do not bring in additional complications to the system to which vibration is being handled. 5.0 Conclusion Vibration involves periodic oscillation of mechanical part about an equilibrium point. Systems that have oscillating and moving parts within them experience this kind of oscillations which eventually amounts to vibration. In situations that vibration causes undesirable results in the mechanical system, vibration needs to be addressed. Passive reduction of vibration involves vibration damping, structural modification, parametric modification and protection of the vibration reason. Active vibration on the other hand involves the methods that lead to parametric and structural adjustments of the systems that are vibrating. In the design of mechanical system effort should be taken to ensure that vibration is totally eliminated or is within safe limits. 6.0 References Dealnt, T 2000, ‘System Stability’, Technology and Engineering Journal, Vol. 12, No. 7, pp. 916- 1012. Elias, K 2010, ‘Vibration reduction techniques in mechanical systems’, Journal Advanced Control Engineering, Vol. 8, no.1-2, pp. 6-13. Kostúr, K. & Phan H 1994, ‘The Design of Structure Simulation System for Heat Aggregates’. Material Manufacturing Engineering, Vol. 1, no.1-2, pp. 6-71. Tirms, B & Chung, M 1984, ‘Structure vibrations,’ Journal of Structural Engineering, ASCE, Vol. 114, no. 1, pp. 41-112. Vestlel, N. & Prisca, R 1974, ‘ Mechanical Systems Design,’ Journal of the Structural Division, Vol. 2, no. 1, pp. 12-19. Read More