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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.
P S K Narasimha Murthy et al IJMEIT Volume 2 Issue 9 September 2014 Page 755
IJMEIT// Vol. 2 Iss.9 //September //Page No: 754-760//ISSN-2348-196x
: 2348-196x
[2014]
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 =
P S K Narasimha Murthy et al IJMEIT Volume 2 Issue 9 September 2014 Page 756
IJMEIT// Vol. 2 Iss.9 //September //Page No: 754-760//ISSN-2348-196x
: 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
P S K Narasimha Murthy et al IJMEIT Volume 2 Issue 9 September 2014 Page 757
IJMEIT// Vol. 2 Iss.9 //September //Page No: 754-760//ISSN-2348-196x
: 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
P S K Narasimha Murthy et al IJMEIT Volume 2 Issue 9 September 2014 Page 758
IJMEIT// Vol. 2 Iss.9 //September //Page No: 754-760//ISSN-2348-196x
: 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
P S K Narasimha Murthy et al IJMEIT Volume 2 Issue 9 September 2014 Page 759
IJMEIT// Vol. 2 Iss.9 //September //Page No: 754-760//ISSN-2348-196x
: 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
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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