ijmeit// vol. 2 iss.9 //september //page no: 754-760//issn ...igmpublication.org/ijmeit...

P S K Narasimha Murthy et al IJMEIT Volume 2 Issue 9 September 2014 Page 754

IJMEIT// Vol. 2 Iss.9 //September //Page No: 754-760//ISSN-2348-196x

: 2348-196x

[2014]

Modeling and Analysis (Linear Static) on a Scissor Lift

Authors

P S K Narasimha Murthy1, D Vinod Prabhakara Rao

2, CH Sai Vinay

3

S Ramesh kumar4, K Sai Narayan

5

INTRODUCTION

Now a day's in the mercantile airline and airport

manufacturing industry, ground support

equipments play a major role in assisting airline

(ground) crews. During the chaotic hours of an

airplane arrival, ground crews are busy with the

loading and unloading of luggage, catering

supplies, water and also refuelling the aircraft fuel

tank in order to be prepared for the next scheduled

departure. These routine activities must be

carefully handled according to standard

procedures and protocols of airport system using

definite equipment. Apart from this, safety

concern is given the prime priority [2]. In order to

accomplish the most out of the used areas, scissors

lift platform must be given higher and higher

loading capability, faster moving velocity and

steady starting and stopping motions of the

platform. The scissors lift mechanism is the

crucial constituent part of scissors lift platform,

whose force characteristics will influence the

performance of the whole equipment directly. In

order to solve this force characteristic the basic

model is designed and analysis is done to find the

stress deflections on each and every leg of the lift.

It is significant for ensuring the security of

baggage at high elevation work.

ABSTRACT:

Scissors lift platform has a wide range in industries and commercial uses. It is being operated with the help

of hydraulic cylinder. This paper is about modelling and analysis (Linear Static) on a scissor lift which is

carried out using Solid Works. This designed scissors lift can reach about 7m height placed and fixed on a

platform with rigid base. Whenever a load is applied on the top of the platform, every post leg of the lift is

subjected to displacement, stress, and strain. In this paper investigations and tabulated results of the

displacement, stress and strain values, and the observations with regard to whether there is a change in

these parameters on every leg when the lift is at the maximum height and whether these parameters get

decreased when the lift height is rendered minimum, are proposed. The outcome of this work is presented in

the form of analytical results which are carried out by considering three different materials at different

heights, the observations of their behaviour are tabulated.



: 2348-196x

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Determination of the main parameters:

1 Maximum working height of scissor lift

2 Length of a link 1500mm

3 Area of platform

4 Rated moving velocity upward

5 Rated moving velocity downward 6m/min

THE DESIGN AND MODELLING PHASE

In this research, Solid Works software was the

main CAD solid modelling software used. With

its extensive features and powerful modelling

tools, it is fully utilized in the CAD modelling

stage. The scissors lifts comprises of major

components that are being assembled together to

form complete scissors lifts for catering the hi-

lift[1]. The post legs and base are two major parts

that make up the whole scissors lifts binding

together with bearings and centre pins. When

modelling the parts, every child parts are saved as

individual parts whereby when assembling the

parts, all modelled child parts are then retrieved

back to be assembled to build the whole scissors

lifts as a complete assembly as shows the

Figure (1). Scissors lift flat form designed in solid

works fig (1)

DEFLECTION CALCULATION

The maximum allowable platform edge deflection

calculation using the ANSI Standard MH29.1-

2003 Safety Requirements for Industrial Scissors

Lifts (Revision on ANSI MH29.1-1994) is using

Equation (1) is[3]

D =

D = Maximum allowable platform edge deflection

in (mm)

n = Number of vertically stacked pantograph leg

sections

L = Platform length (mm)

W = Platform width (mm)

The numbers of vertically stacked post leg

sections are the number of scissors located on a

single application .

For the catering hi-lift used in this research, five

vertically stacked post leg section was identified.

From Equation (1), the maximum allowable

platform edge deflection is calculated as below.

D =



: 2348-196x

[2014]

FINITE ELEMENT ANALYSIS (FEA)

SIMULATION

To run the FEA simulation using solid works

software, it is necessary to generate the Finite

Element Model of the scissors lifts structure. This

is because, since the early days much progress has

been made to finite element method of analysis

and today it is viewed as a general procedure of

solving discrete problems posed by

mathematically defined statements with multiple

of numerical experiments that can be carried

out[2] . However, all the post legs are used in this

analysis because taking into account, the post leg

lift and sustain the load exerted on it will be safe

during operation.

RESULTS AND DISCUSSION

The results were calculated for three different

materials (alloy steel, aluminium, and stainless

steel) at three different platform heights (at

5700mm, 3100mm, 2000 mm). These three

different materials and platform heights are

analysed and results are shown in the tabular

column.

Displacement values of scissors lift at height of

3100(mm) for alloy steel material.

Von-misses stress values of scissors lift at height

of 3100(mm) for alloy steel material

Strain values of scissors lift at height of

3100(mm) for alloy steel material-

The below tabulated values are calculated for the

applied load of 1000 Newton and 2000 Newton

force on the lift platform.Table-1 and table-2

shows the stress, displacement, strain maximum

and minimum values of the scissors lift for alloy

steel material. table-2 shows the values for

aluminium and table-3 shoes the values for

stainless steel for two different loads. From the

below tabulated values it is found that at 1000N,

when the lift is at maximum height then the stress

concentration and deflection is more for

aluminium least for alloy steel. At 20000N, it is

more for stainless steel. The maximum deflection

for aluminium platform at maximum height(5700



: 2348-196x

[2014]

mm) for 1000N force is 6.214mm, from

equation(1) it is found that the maximum

deflection can be up to 70mm so this model is

sustainable at this load. As the lift height is

decreasing the stress and strain and displacements

are also decreasing resulting that at minimum

height the model is more sustainable. Again same

analysis at that same height and materials where

conducted by changing the load parameter in

order to see the changes in those parameters, as

shown in the below tabular columns and graphs.

Alloy steels.(table-1) at 1000N

Sl.no

Height

Displacement

Max Min

Strain

Max Min

Stress

Max Min

1 2000 mm 5.072e-001 8.502e-003 3.317e-005 3.127e-009 12,259,360.0 415.7

2 3100 mm 7.989e-001 9.497e-003 3.651e-005 2.219e-009 13,321,603.0 485.4

3 5700 mm 2.038e+000 8.412e-003 4.433e-005 8.225e-010 15,590,318.0 186.3

Aluminium.(table-2) 1000N

Sl. no

Height

Displacement

Max Min

Strain

Max Min

Stress

Max Min

1 2000 mm 1.547e+000 2.583e-002 1.054e-004 1.023e-008 12,149,051.0 228.8

2 3100 mm 2.435e+000 2.887e-002 1.159e-004 7.266e-009 13,300,705.0 330.6

3 5700 mm 6.214e+000 2.556e-002 1.409e-004 2.384e-009 15,620,885.0 374.6

Stainless Steel.(table-3) 1000N

Sl. no

Height

Displacement

Max Min

Strain

Max Min

Stress

Max Min

1 2000 mm 5.326e-001 8.927e-003 3.483e-005 3.284e-009 12,259,360.0 415.7

2 3100 mm 8.388e-001 9.972e-003 3.833e-005 2.330e-009 13,321,603.0 485.4

3 5700 mm 2.140e+000 8.833e-003 4.654e-005 8.637e-010 15,590,318.0 186.3

Alloy Steels.(table-4) at 20000N

Sl. no

Height

Displacement

Max Min

Strain

Max Min

Stress

Max Min

1 2000 mm 1.112e+001 1.745e-001 6.849e-004 5.629e-008 242,456,368 3,606.3

2 3100 mm 1.580e+001 1.90e-001 7.291e-004 4.832e-008 258,012,752.0 3,184.7

3 5700 mm 4.689e+001 1.753e-001 9.011e-004 6.131e-008 147,505,232.0 3798.6



: 2348-196x

[2014]

Aluminium.(table-5) 20000N

Sl. no

Height

Displacement

Max Min

Strain

Max Min

Stress

Max Min

1 2000 mm 3.388e+001 5.301e-001 2.159e-003 1.735e-007 240,805,504.0 2,909.7

2 3100 mm 4.817e+001 5.775e-001 2.317e-003 1.072e-007 258,586,560.0 3,000.7

3 5700 mm 4.689e+001 1.753e-001 9.011e-004 6.131e-008 318,324,128.0 6,865.4

Stainless Steel.(table-6) 20000N

Sl.no

Height

Displacement

Max Min

Strain

Max Min

Stress

Max Min

1 2000 mm 1.167e+001 1.832e-001 7.192e-004 5.910e-008 242,456,368.0 3,606.3

2 3100 mm 1.659e+001 1.995e-001 7.655e-004 5.074e-008 258,012,752.0 3,184.7

3 5700 mm 4.975e+001 1.843e-001 9.501e-004 7.172e-008 319,756,736.0 6,763.3

Displacement at 1000N Displacement at 20000N

Displacement at 1000N Displacement at 20000N

0.00E+00 2.00E+01 4.00E+01 6.00E+01 8.00E+01 1.00E+02 1.20E+02 1.40E+02 5700

mm 3100mm 2000mm

0.00E+00 2.00E+01 4.00E+01 6.00E+01 8.00E+01 1.00E+02 1.20E+02 1.40E+02

5700 mm 3100 mm 2000 mm

0.00E+00 5.00E-05 1.00E-04 1.50E-04 2.00E-04 2.50E-04 3.00E-04 3.50E-04 4.00E-04

5700 mm

3100 mm

2000 mm

0.00E+00 1.00E-03 2.00E-03 3.00E-03 4.00E-03 5.00E-03 6.00E-03

5700 mm

3100 mm

2000 mm



: 2348-196x

[2014]

Strain at 1000N Strain at 20000N

Stress 1000N Stress 20000N

CONCLUSION

(1) Effect of load on scissors lift through

performing exact finite element analyses of the lift

with different heights and materials are calculated.

In order to find out the maximum deflection

mathematical programming method is used. At

three different positions stress, strain and

displacements are calculated.

(2)When the lift is at the maximum height then for

a given load the stress, strain and deflection is

higher compared to the minimum height of the

lift. All these parameters are proportional to the

lift height.

(3) When the load is 20000 N on the lift it reaches

to its yield strength within the limits of the

maximum stress being acted upon. The lift cannot

sustain this load. The deflection is also maximum

at this load thus the lift fails at this condition.

ACKNOWLEDGMENT

The authors would like to thank Dr A.Srinath and

Ch.Sai Vinay who provided us with the modelling

data.

REFERENCES

1. Tian Hongyu, Design and Simulation

Based on Pro/E for a Hydraulic Lift

Platform in Scissors Type, in science

direct (march 2011), vol 16, pp 772-781.

2. Helmi Rashid, Design Review of Scissors

Lifts Structure for Commercial Aircraft

Ground Support Equipment using Finite

Element Analysis, in science direct (dec

2012), vol 41, pp 1696-1701

3. James R. Harris, Fall arrest characteristics

of a scissor lift, in national safety council

(Available from 15 April 2010) vol 41, pp

213-220.

0.00

10,000,000.00

20,000,000.00

30,000,000.00

40,000,000.00

50,000,000.00 5700 mm 3100 mm 2000 mm

0 200,000,000 400,000,000 600,000,000 800,000,000

1,000,000,000

5700 mm

3100 mm

2000 mm

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