December 24, 2013

Basic Hydraulic System Test Questions

The following items will test your grasp of the material covered in this lesson. There is only one correct answer for each item. When you have completed the exercise, check your answers with the answer key that follows. If you answer any item incorrectly, study again that part of the lesson which contains the portion involved.

December 21, 2013

Mechanical Engineering Question Bank Objective Type

Question Bank of Mechanical Engineering Objective Type

Questions

Part1 :

True or False Type Statements


Organisation of Mech. Engg. Deptt.
1. The Mechanical Engineering Department employs 25% of the overall staff
strength of Indian Railways.
2. RCF is situated in Patiala.
3. Repower-packing of Diesel Locos is carried out in DLW.
4. COFMOW deals with New Maintenance Practices for Workshops.
5. Diesel sheds are under the administrative control of CWE

November 06, 2013

July 21, 2013

EXPLODE RENDER ANIMATE

rticle FROM Solid Edge Explode — Render — Animate application  Publication Number  spse0154

Defining motors

 
 
 
 
 
· There are two types of motors that can be defined in Solid Edge: rotational and linear.· You use motor features to help you observe how a set of under-constrained parts will move relative to the part you define as a motor
  1. · This allows you to design and simulate complex mechanisms where the movement of a set of interrelated parts needs to be simulated.
  2. Motor command
    · Defines a rotational or linear motor using an element on a selected part.
    · You can then use the Simulate Motor command to display a kinematic simulation of the motion in an assembly.
    · You use motor features to help you observe how a set of under-constrained parts will move relative to the part you define as a motor.  This allows you to design and simulate complex mechanisms where the movement of a set of interrelated parts needs to be simulated.
    · This is useful when working with assemblies that contain moving parts such as gears, pulleys, crankshafts, parts that travel in grooves or slots, and hydraulic or pneumatic actuators.
    For example, you can specify that a crankshaft part (A) in a mechanism rotates around an axis you specify (B).
    · You can then use the Motor Simulation command to playback a kinematic simulation of how the under-constrained parts in the assembly move.
    · Press F5 to replay the animation
    · You can define properties for the motor, such as the type of motor, the motor rate or speed, motor direction, and any limits you may want to place on the motor.
    · When you define a motor feature using the Motor command, an entry is added for the motor feature to PathFinder.
    · You can select the motor entry in PathFinder to edit the motor feature later.
    Types
    You can define the following types of motors:
    1 .Rotation 2. Linear
    Steps
    The basic steps for defining a motor are:
    • Specify the type of motor you want, Rotation or Linear.
    • Select the part you want to act as a motor.
    • Define the movement axis.
    • Specify the motor rate and limits.
    Specifying Motor Type
    The Motor Type list on the command bar allows you to define the type of motor you want. You can specify whether you want the motor type to be Rotation or Linear.
    Selecting the Part
    • You can only select a part that is under-constrained, or has relationships suppressed.
    • The assembly should also be under-constrained such that the mechanism is free to move in the proper axes.
    Defining the Movement Axis
    · Depending on the motor type you specify, you can select faces, edges, or cylindrical axes to define the motor axis.
    · For example, to define a Rotary motor, you can select cylindrical faces, cylindrical edges, or cylindrical axes.
    Specifying the Motor Rate and Limits
    · The Motor Value and Limits options on the command bar allow you to specify the speed or rate you want the motor operate at, and any limits on the travel you want to impose.
    · For example, you may want to specify that a rotational motor rotates at 1750 revolutions per minute, and makes two complete revolutions (720 degrees).
    · You can set the working units you want to use for the angular and linear velocity of a motor using the Advanced Units button on the Units tab of the File Properties dialog box, on the File menu.
    Motor Definition and Simulation Guidelines
    · You can define as many motors as you want in an assembly.
    · When you define multiple motors in an assembly, use the Motor Group Properties dialog box, available with the Simulate Motor command and the Animation Editor tool to specify which motors you want to use,
    · whether you want to detect collisions during the simulation, and so forth.
    · When working with more than one motor, use the Animation Editor tool to specify when the motors start time, duration time and stop time for each motor.
    · This allows you to design and simulate complex mechanisms where the timing and positioning of the parts is critical to understanding the behavior of the mechanism.
    Note
    · Only motors in the active assembly participate in a motor simulation.
    · If you want subassembly parts to move in response to a motor simulation, you need to make the subassembly adjustable, using the Adjustable Assembly command on the PathFinder shortcut menu.
    Simulate Motor command
    · Display a kinematic simulation of motion in an assembly.
    · You use motor features to define how a set of interrelated parts will move.
    · This is useful when working with assemblies that contain crankshafts, gears, pulleys, and hydraulic or pneumatic actuators.
    · When you click the Simulate Motor button, the Motor Group Properties dialog box is displayed,
    · so you can specify which motors you want to use, whether you want to detect collisions during the simulation, and so forth.
    · When you click OK, the Animation Editor tool is displayed so you can run the simulation.
    · To run the simulation, click the Play button.
    Note
    · The Simulate Motor command contains a subset of the Animation Editor functionality.
    · To access the full functionality of the Animation Editor tool, you must use the Animation Editor command in the Explode-Render-Animate application.
    · To access the Explode-Render-Animate application, on the Tools tab, click Explode-Render-Animate.
    Motor Group Properties dialog box
    No Analysis
    Allows you to move under-constrained parts and observe the results.
    Detect Collisions
    Allows you to detect collisions during motor animation.
    Physical Motion
    • Allows you to simulate physical motion between parts.
    • This option detects contact between unconstrained surfaces and applies temporary constraints between the contacting surfaces.
    • This makes it possible to analyze motion in mechanisms that contain gears and other forms of sliding contact
    Motor Duration
    Specifies how the motor duration is defined.
    Use Motor Limits as Duration if Defined
    Specifies that the motor limits define the duration.
  3. Default Motor Duration
  4. Specifies the motor duration in seconds. You can type a value.
    Available Motors
    Lists the available motors. You can use the Add and Remove buttons to add motors to and remove motors from the Motors in Animation list.
    Add
    Adds a motor to the Motors in Animation list.
    Remove
    Removes a motor from the Motors in Animation list.
    Motors in Animation
    Lists the motors that will be used in the animation.
    Activity: Motor
    • In this activity, you will assign a motor to a part in an assembly.
    • The type of motor will be a rotational type and be applied to a gear in a clock.
    • The speed of the motor will be such that the second hand of the clock moves at the operating speed of 1 rpm.
    • The gear relationships are predefined, and by assigning the motor to the appropriate gear, motion can be shown through motor simulation.
    • The motor simulation used here will later be used to create an animation of the clock.

May 24, 2013

wonder rickshaw

  A Kolkata engineer has designed a cycle-rickshaw that uses passenger load to push the vehicle and reduces the puller's drudgery by using bumps on the road for propulsion.

Pratik Kumar Ghosh's wonder vehicle which promises to improve the lives of thousands of rickshaw pullers is easy to make and is also cheap.

"The rickshaw resembles conventional rickshaws and can be assembled with the same parts which are currently in use" Ghosh 55 told IANS about his design that won a union government innovation award.

The innovator who works as an assistant general manager with Shriram EPC Ltd said his design would make bumps and unevenness of the road favourable to the rickshaw puller -- converting the shock and vibration to a propulsive force.

"No parts need to be redesigned. The design of the rickshaw is very simple and its manufacture will be equally easy. The cost of production will be close to the existing ones" he said.

Ghosh's idea won the National Innovation Council's Innovation Challenge to Reduce Worker Drudgery along with six other ideas in April.

"The rickshaws in vogue were designed to carry load without keeping in mind ways to enhance puller's ease. In the long history the vehicle only underwent cosmetic design changes" he said.

In conventional rickshaws the chassis is horizontal and the load acts as dead load without any forward component he said.

"In the proposed rickshaw the chassis is at an angle of 10 degrees to the ground leaning to the front. Any load on the chassis will have a forward component to assist propulsion. These two forward forces will concur and make the muscle power requirement of the puller minimum when the vehicle will start to move" he said.

Also the chassis currently is fixed at all three points with the triangular frame and requires more power to propel.

"But in this design the chassis is hinged at the pedal hub and the two other points are fixed with the frame. Since the hinged point acts as pivot the shock generated by the road is transmitted as a force to the frame and makes the hostile road favourable to the puller" he said.

Also the passenger weight in current rickshaws falls directly on the axle he said.

"But here the seat frame will be tubular and the rear two legs will not swing and remain pressed to the bearing box horizontally converting the downward passenger load to horizontal forward propulsive force" he said.

"More the passenger weight more will be the push."

Ghosh's design is different from the soleckshaws (Solar-Electric Rickshaws) designed by the Council of Scientific and Industrial Research (CSIR) which require new parts and major structural changes.

"I'm an innovator not entrepreneur. I can't manufacture the rickshaws when more than eight million existing rickshaws are to be replaced. Since the production requirement is huge I wish big cycle and rickshaw manufacturers come forward and manufacture the rickshaw" Ghosh told IANS.

"Since the rickshaw pullers will be able to travel long distances with high speed effortlessly it is presumed that these rickshaws will be able to replace autos to some extent and reduce dependence on fuel-based vehicles" he said.

Ghosh who is hoping that manufacturers and state governments looking to help rickshaw pullers will pick up his design said the drawings could be taken from the National Innovation Council.

The other winners of the council's contest from the 468 proposals are a human powered motor by professors and students of IIT Madras; a vessel desk for construction workers by Maharashtra student Raghunath P. Lohar; a display unit for street vendors by IIT Guwahati student Manjunath Butta; a low cost cycle for physically challenged by working professionals from Chennai Ajith T. Alex Aanand Ganesh and Mahesh P.V; and a picking grab for sanitation workers by retired Kolkata engineer Jitendra Nath Das.