This lifting machine is used to carry heavy industrial machinery like lathe from one floor to another. We have analysed the strength and the capacity of this machine. We have checked critical points for failure and suggested design recommendations to increase the capacity to 3 tonnes from the present value of 1.1 tonne. Detailed analysis: http://www.slideshare.net/AhsenParwez/analysis-of-lifting-machine Team members: Ahsen, Ankit, Ankit, Shivam, Anurag, Deepak

1. ME 351A PROJECT
Team members
Ankit Shrivastava (11113)
Ankit Yadav (11115)
Ahsen Parwez (11416)
Deepak Dalakoti (11235)
Shivam Patel (11683)
Anurag Bhatt (11135)
Project Title – Transporters

2. OBJECTIVE
 Design of transporter system in Southern Labs
 Analyzing critical failure locations of the assembly
 Estimating present load capacity of the machine
 Proposed design changes for a load of 3 tonnes

3. SUB SYSTEMS
 Pneumatics and Pulley
 Primarily lifting mechanism
 Pneumatic piston cylinder arrangement
 Powered by motor
 Main Frame
 Supports carriage and pulleys
 Safety features like anti roll bar
 Carriage
 Platform reinforced by square steel bars
 Connected to chain and pulley assembly

4. Design Specifications
FBD and Analysis of
sub-system
Is allowable load
under 3 tonnes?
Identify critical
locations with n =3
Proceed to next sub
system
Design alterations
NO
YES
Choose minimum of all
loads as the rated load

5. PNEUMATICS AND PULLEY
Possible modes of failure
 Rupture of pneumatic cylinder
 Buckling of piston rod
 Weld failure of Pulley shaft
 T section yielding
 Chain Design

6. ESTIMATING CRITICAL LOADS
Failure Mode Critical load with n = 3 (in tonnes)
Rupture of pneumatic cylinder 10.72
Buckling of piston rod 81
Weld failure of Pulley shaft 3.05
T section yielding 9.9
Chain failure ASTM 60 designed for 3 tons
 Critical element - pulley shaft
 Maximum allowable load = 3.05 tonnes
 Satisfies design requirement of 3 tonnes
 No design modifications required

7. MAIN FRAME
Modes of failure
 Failure of load carrying bar
 Weld failure of welded chain
 Anti roll bar failure

8. ESTIMATING CRITICAL LOADS
Modes of failure Critical loads with n =3 (in tonnes)
Failure of load carrying bar 1.1
Weld failure of welded chain 9.8
Anti roll bar 4.2
 Critical location – load carrying bar
 Maximum allowable load < 3 tonnes
 Design changes required

9. DESIGN CHANGES FOR WEIGHT CARRYING BAR
 Increase weld length and leg size
 Maximum Load is 2.4 tons for h =5mm and d = 5mm
 Maximum length and leg size limited by dimensions of bar
 Change material
 440 Q&T steel
 Maximum load is 7.32 tonnes
 Economically unfeasible
 Change weld pattern
 Square weld
 Maximum load = 3.26 tonnes
 Most feasible solution
 Compromised Factor of Safety
 Measure of last resort
 For n = 2 , critical 4.8 tons

10. CARRIAGE
Modes of failure
 Weight sharing by square
reinforcing side bars
 Shear failure of reinforcing side
bars

11. ESTIMATING CRITICAL LOADS
Modes of failure Maximum load with n = 3 (in tonnes)
Weight sharing by square reinforcing
side bars
26.42
Shear failure of reinforcing side bars 6.73
 Critical location – shear failure of reinforcing
side bars
 Maximum allowable load = 6.73 tonnes
 Satisfies design requirement of 3 tonnes
 No design changes required

12. FINITE ELEMENT ANALYSIS
 Analysis done using design principles was cross checked using Finite
element packages commercially available.
 Inventor was used to create a CAD model of the critical systems and
analysis was done.
 We plotted the factor of safety for the structure while taking load as 3
tonnes.
 Also, displacements of critical elements were plotted to check assumptions
made during theoretical analysis

13. LOAD CARRYING BAR

14. LOAD CARRYING BAR

15. LOAD CARRYING BAR

16. LOAD CARRYING BAR

17. CARRIAGE WELDS & BENDING

18. CARRIAGE WELDS & BENDING – Y displacements

19. CARRIAGE WELDS & BENDING- Safety factors

20. CARRIAGE WELDS & BENDING- Safety factors

21. DESIGN SHORTCOMINGS & PROPOSED
CHANGES
 Exact length of Piston rod unknown
 Novel Use of chain with pulley modelled as pulley with cable
 Mixture of butt & fillet welds in reinforcement bars taken as all fillet welds
(inherently conservative as fillet welds are weak)
 PROPOSED CHANGE :
 Load carrying bar most critical & fails at weld to connecting plate
 Design change made : weld pattern change
 Alternative: Add reinforcement to bar like in a truss for load sharing and
larger capacity enhancement and reliability