Vibration and Its Implications - Term Paper Example

Running Header: Vibration and Its Implications Student’s Name: Instructor’s Name: Course Code & Name: Date of Submission: Vibration and Its Implications Contents Contents 2 Introduction 3 Situations where vibration needs to be addressed 3 Passive reduction of Vibration 4 Active reduction of Vibration 6 Design Process 7 Conclusion 7 References 9 Introduction Vibration is the continuous or repetitive periodic oscillation of a system with respect to a fixed point (Bialas 2006, p. 68). In mechanical systems, the mechanical oscillation may either be desirable or undesirable. The desirable oscillation is the one which is necessary for the mechanical system to function properly. Undesirable oscillation on the other hand is unwanted since it creates wastage of energy. Most of the mechanically developed machines and systems consider vibrations as undesirable. This paper seeks to discuss the implications and the problems that vibration has for the mechanical design of components. Situations where vibration needs to be addressed In course of operation, any mechanical system experiences some form of vibration which if they are fully minimized then the system would stop working (Ellingwood & Tallin 1984, p. 11). Sometimes vibration may reach a level such that it becomes difficult to maintain the system in which that vibration occurs. It is this kind of situation that vibration becomes a problem therefore requiring to be urgently addressed. Whenever the machine is operating, it should be in a state that it does not risk destroying other machines that are near it or the human being operating it. In mechanical machines where machine parts are interdependent and interlocked, vibration of machine in one section may cause the vibration signals to be amplified in the other sections which may cause the entire system to be at risk. Some control mechanical control and operating systems have multiple stages which might amplify or dangerously change the course of the vibration signals to other parts of the system (Thomas 2004). This is a major challenge to control systems where signal level of vibration may take a different dangerous form on some other related part of the machine making risking the entire system from destruction. In this case, the design of such system should be familiar with the limits that are likely to occur based on vibration signal generated in any section of the system and the likely consequence. From this, the minimum vibration occurring at any part of the mechanical machine should be known, so that whenever this limit is reached, control systems either stops the entire system, sends a warning alarm or deploys a mechanism to address the situation. Vibration may also reach a level that it poses danger to the person who is working on it. In this case, vibration needs to be addressed so that it is within the safe working conditions of human being. For the moving parts of a machine, it is therefore impossible to completely eliminate vibration. What is important though is to make sure that vibration happens within safe limits. Passive reduction of Vibration Passive measure of reducing the vibrations in machines refers to the construction elements that are added to the machine to reduce vibration in the main machine (Bialas 2006, p. 69). These additional elements of vibro-isolation are not part of the integral element of machine structure but are additional elements put into practice in order to propagate mechanical vibration signals like those of mechanical filters of the signals. One way to do this is by use of control system. A control system measures the strength, nature and signal form of vibration that arises. The control system then designs a vibration signal that cancels the original unwanted signals that causes instability due to vibration. As a result of canceling out of these signals, the entire mechanical system stabilizes. In this case, a sensor is put at the specific part that triggers vibration of the mechanical system. The work of this sensor is to monitor and record the signal that of vibration. The findings of this sensor are passed to control system which calculates the precise wave form that is required to counter the vibrations. It then generates the counter vibration waveforms, changes the time shift to match that of generating signal before sending them back to the vibrating part. This technique employs damping technique, where one form of energy is used to cancel another form of energy therefore leaving the system in a neutral and stable position. The control loop used could be either feedback or feed forward loop. Mechanical vibration filters are another way of reducing vibration. In this case, at the strategic parts of the machine where vibration is dominant, the vibration filters are put in place in such a way that they prevents they filters out any vibration signal (Thomas 2004). Specialized filters may be designed in a form that they can transform the vibration they absorb to other forms of energy. Through use of transducers, the vibration signals may be converted to electrical power or other form of energy that is desirable for use in the environment that the plant is set up. This way, the vibrations are not passed to any other part or sections of the system which significantly reduces vibration to the entire vibration system. This method has the advantage that it is very easy to adjust the vibration levels since the system that manages vibration is isolated from the main system that does work. It is therefore more efficient, cheaper to implement and may not require large amount of power. However the system it brings bulkiness to the main system which also comes with additional cost of design and materials required for construction. Active reduction of Vibration Active reduction of vibration is aimed to reducing vibrations on the subsystems. It further aims to eliminate or reduce the formation of machine vibration (Bialas 2006, p. 69). In this case, reduction of the vibrations from the source of vibration source is what is considered to be of ultimate importance. In the design of mechanical system, during simulation, it is possible to identify the areas that can be the root cause of vibration when the system is running in the real situation. Identifying this, the design is altered to ensure the kind of vibrations generated are at their lowest level or do not interfere with the rest of the system. The methods of active vibration reduction are divided into adjusting or controlling processes of the mechanical vibration. Motion control of object means you supply a command signal from outside the system to the system (Wiss & Parmelee 1974, p. 127). The signal sent here does not depend on the current situation of the object but is rather influenced by the program that was developed previously. This means that signals are continuously sent to stabilize the system without necessarily determining the extent of vibration. The control may be using other principles of stabilizing other than countering the actual signals that cause the vibration. The adjustment process on the other hand depends on the current condition of the system. In this case, the object motion is adjusted depending on the conditions that the system is in. To implement this, additional elements like the output sensors, control unit and the executive devices are in cooperated in the system (Murray 1975, p. 103). The role of the additional features is to identify the extent of vibration and then use the control devices to release the right amount of energy required to stabilize the system. Design Process In the design of the mechanical systems, the manufactures and the designers are faced with the problem of preventing the unwanted effects to the operation of the newly designed machines to ensure that they meet standard requirements (Ellingwood & Tallin 1984, p. 10). Vibration reductions are additional features that are required to be added by the designers in the construction of such system (Murray 1975, p. 103). The first stage involves analyzing the problem at hand and how a machine can be designed to solve that problem. The designer comes up with machine specifications which are to be in cooperated in the design. In this case the designer determines what the intended purpose of the system and how it is going to meet the objectives. The designer analyses all the possible option then comes with one model which best fits the intended need of the system. The second part of the design involves coming up with a design that not only meets the specifications of the machine but also performs minimizes the operation cost of the machine itself. It is at this stage that the issues such as vibrations are addressed. A thorough test is carries out, either in simulation or model to weighing out the various options that needs to be there to be included in the model to ensure that it best minimizes these effects. The best model that passes the two stages is then implemented and maintenance instructions developed for the users. Conclusion Vibration is the repetitive oscillation of a mechanical system with respect to a given point. In most cases vibration causes undesirable results to the system that is being operated. Major situations that issue of vibration needs to be addressed are the situations where vibration is to the magnitude that threatens the hazard of the machine itself or the operators working within its environment. Two types of vibration reduction mechanism exist, passive and active. Passive measures involves additional of constructional elements, isolated from the main system whose aim is to curb vibration. On the other hand active measures aim at eliminating the reasons for the formation of vibration. The design process involves set of procedure ranging from analysis, design then implementation aiming to produce a highly efficient mechanical system. References Bialas, K 2006, ‘Comparison of passive and active reduction of mechanical systems’, Journal of Achievements in Material Manufacturing Engineering, Vol. 18, no.1-2, pp. 68-73. Ellingwood, B & Tallin, M 1984, ‘Structural Serviceability: Floor Vibrations,’ Journal of Structural Engineering, ASCE, Vol. 110, no. 2, pp. 6-12. Murray, T 1975, ‘Design to Prevent Floor Vibrations’, Engineering Journal, AISC, Vol. 12, No. 3, pp. 96-120. Thomas, S 2004, Vibration Problems, Adelaide University, viewed 12 January 2012, < http://www.gadgetonline.com/Vibration.htm>. Wiss, J. & Parmelee, R 1974, ‘Human Perception of Transient Vibrations,’ Journal of the Structural Division, Vol. 7, no. 2, pp. 126-130. Read More