Wednesday, May 6, 2020
Mechanisms and Dynamics of Machinery
Questions: Write a report concerning the planar mechanism. In your report, you must: 1. Describe the links and pairs and calculate the mobility. 2. Draw a fully dimensioned drawing of the mechanism shown, making reasonable estimates of all dimensions necessary to define the location of all points A to G. 3. Estimate the mass of the door. You may assume that other mechanism components are massless. 4. Plot the locus of all points from door closed to door open. 5. Write vector equations relating the location of all points as a function of. 6. Use your equations derived in 5 to plot the x and y position of all points as a function of. 7. Write vector equations relating the velocity of all points as a function of for constant = 1 rad/s. 8. Show velocity vectors, to scale, for all points when the door is fully open, fully closed, = 0 and = -30. Assume that = 1 rad/s and the door is opening in all cases. Answers: The versatility of a component is the quantity of degrees of freedom with which it might move. This thought is numerically comparable to the measurement of the arrangement set of the kinematic circle conditions for the system. It is well realized that the traditional Grubler-Kutzbach recipes for portability cannot be right for uncommon classes of components, and considerably more refined medicines taking into account relocation bunches neglect to effectively anticipate the portability of alleged "incomprehensible" systems. This article talks about how late results from numerical mathematical geometry can be connected to the subject of instrument portability. Specifically, given a get together design of a component and its circle conditions, a nearby measurement test places limits on the portability of the related get together mode. An openly accessible programming code makes the thought simple to apply in the kinematics area. The given jamb-type garage door opening mechanism is as fo llows- Give n a chance to be the no. of connections in a component out of which, one is settled, and let j be the no. of straightforward hinges (i.e., those interface two connections.) Now, as the (n-1) joins move in a plane, without any associations, each has 3 level of opportunity; 2 directions are required to determine the area of any reference point on the connection and 1 to indicate the introduction of the connection. When we associate the links there can't be any relative interpretation between them and one and only facilitate is important to indicate their relative orientation. Thus, 2 degrees of opportunity (interpretation) are lost, and one and only level of flexibility (rotational) is cleared out. In this way, no. of degrees of opportunity is: F=3(n-1)- 2j Most instruments are obliged, ie F=1. In this manner the above connection gets to be, 2j-3n+4=0 This is called Grubler's Criterion. Disappointment of Grubler's standard, A higher pair has 2 degrees of flexibility .Following the same contention as some time recently, The degrees of opportunity of an instrument having higher sets can be composed as, F=3(n-1)- 2j-h Frequently a few components have an excess level of flexibility. On the off chance that a connection can move without creating any development in whatever is left of the instrument, then the connection is said to have a repetitive level of freedo 1. As there are total 5 links and all are lower pair links therefore we can say that the number of joints is also 5, thus calculating the mobility for the mechanism- i.e. the mobility of the mechanism is. 2. Now drawing the locations with the suitable dimensions- 3. Now estimating the mass of the door to be 50 kg Thus the weight of the door = Mg Thus the weight of the door = 50*9.81 Thus the weight of the door = 490.5 N Now assuming the angle GOD = 300 and for this angle the force required will be- 4. Locus of all points for the closed door- When the door will be closed the location of the points will be- The location of the points G, H, O, and A will be same. The location of the point C will become A and the location of E will be C. When the door will be open the location of the points will be- The location of the points G, H, O, and A will be same. The location of the point C will become D and the location of E will be parallel to G, and the location of the point F will be at the point C. 5. The vector equations regarding the location of the points can be written as- In the similar way the vector loop equation can be written as- This vector equation in Cartesian coordinates can be written as- 6. The location can be plotted as- 0 30 45 60 Location 0 11.54 17.45 28.95 7. When the angular velocity Writing the velocity vector equations- Where- a is the location of the points. Then the angle can be calculated as- Location would be- Therefore the velocity vector for location Therefore the velocity vector for location 8. When the door is fully open- When the door is fully closed- When The velocity vector for location The velocity vector for location References An Improved Door Closer. (1888). Sci Am, 58(14), pp.212-212. EDITORIAL: When Is a Door Closer 'Work Equipment'?. (2009). Statute Law Review, 30(1), p.iii-v. Johnson, J. (1988). Mixing Humans and Nonhumans Together: The Sociology of a Door-Closer. Social Problems, 35(3), pp.298-310. Johnson, J. (1988). Mixing Humans and Nonhumans Together: The Sociology of a Door-Closer. Social Problems, 35(3), pp.298-310. Mullins, L. (1973). Closer Still to a Mechanism of Anesthesia. Anesthesiology, 38(3), pp.205-206. Wong, Y. (n.d.). Wolves at the Door: A Closer Look at Hedge Fund Activism. SSRN Electronic Journal.
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.