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Materials Today: Proceedings 22 (2020) 3320–3329 www.materialstoday.com/proceedings

ICMMM 2019

Structural Analysis of Quadcopter Frame

Rahul Singha, Rajeev Kumara, Abhishek Mishrab*, Anshul Agarwala
a
Department of Electrical and Electronics Engineering, National Institute of Technology Delhi, Sector A-7, Narela, Delhi – 110040, INDIA
b
Department of Mechanical Engineering, National Institute of Technology Delhi, Sector A-7, Narela, Delhi – 110040, INDIA

Abstract

Quadcopter is an advance highly maneuverable aircraft which has a simple design and structure. It has high load carrying
capacity and other characteristics. Quadcopter is one of the UAV (Unmanned aerial vehicle) which is used to lift, carry, observe,
rescue and collect data from one place to another in lesser time and without taking much space and cost. It can be used for
surveillance purpose and military operations. The static and dynamic characteristics of the structure of quadcopter have been
analyzed by determining and analyzing the dynamics of the quadcopter. This paper describes the overall design of quadcopter
frame model, then analyzing the frame with commercial Finite element code ANSYS 18.0 (Academic research). Selecting the
necessary material and structure that meets the strength and stiffness of requirement of the system.n
© 2019 Elsevier Ltd. All rights reserved.
Peer-review under responsibility of the scientific committee of the 2nd International Conference on Materials Manufacturing and
Modelling, ICMMM – 2019.

Keywords: Arm; Base Plate; FEM Analysis; Frame; Static; Dynamic

1. Introduction

Quadcopter is a multirotor UAV with motor placed in four corners of a cross shaped frame. It is operated by four
motors to move in the air as shown in the paper [1]. It’s light weight and high thrust generating capacity of motors
that allow it to increase its weight lifting capability which will be more with electronic components placed on it for
its operation. Structural analysis is one of the important application of the finite element method. The
term structural implies not only civil engineering structures, but also naval, aeronautical, and mechanical structures
such as ship hulls, bodies of aircraft, machine housings, mechanical components such as pistons, machine parts and

* Abhishek Mishra. Tel.: +91-11-33861212; fax: +91-11-27787503.

E-mail address: abhishekmishra@nitdelhi.ac.in

2214-7853© 2019 Elsevier Ltd. All rights reserved.

Peer-review under responsibility of the scientific committee of the 2nd International Conference on Materials Manufacturing and Modelling,
ICMMM – 2019.
 R. Singh et al. / Materials Today: Proceedings 22 (2020) 3320–3329 3321

so on. Inaccordance with the previous researches on the frame of dimension of 495 mm X 363 mm, the static
analysis of quadcopter frame depicts that the maximum deformation of 0.8963mm which is obtained at the outer
edge of the arm of quadcopter and the maximum stress of 39.6 MPa at the inner side of the arm attached to the inner
plate [2].
The concept of quadcopter design is based on information available in existing literature and further
modifications are applied from time to time [2]. Quadcopter frame size is chosen first so that motor and propeller
will be chosen accordingly [3]. The designing of frame is done in CATIA software [4].Knowing the material
properties of quadcopter frame, static dynamics is done. Thereafter dynamic analyses are done by knowing the
amount of force applied in the air using the ANSYS software [5]. Body frame strength and rigidity of quadcopter
frame can be analyzed based on calculation of magnitude of thrust produced by each motor,. The propeller of 8 inch
and motor of 1400 KVA is used to analyze the thrust of each motor [6]. This thrust is used to determine the
structural analysis of the quadcopter frame.

2. Methodology

The structural analysis of the frame of the quadcopter invloves the following steps as shown in the Fig 1.

Fig. 1. Block diagram of methodology

The very first stage involves the selection of the motor, frame and the propeller for the analysis purpose [7]. As
the specific size propellers and motors developed a specific amount of the maximum thrust force. Thereafter the
mechanical model of the frame is done by taking the dimesions of the frame either from source or from manual
measurement. For the mechanical modelling of the frame of the quadcopter, CATIA software is used. Then static
and dynamic analysis of the mechanial model is done using the ANSYS software and the contours are obtained
accordingly by inserting the geometry of the mechanical model and the properties of the frame material. In the last
part of dynamic analysis, the velocity at different instant is inserted to get the results and a downward force equals to
the weight of the quadcopter is applied in the opposite direction.

3. Quadcopter Frame Modeling

While designing the body frame of quadcopter, it is important to know the total weight of the quadcopter which
includes weight of electronic component, frame, motor, propeller, sensor [1]. For this model, size of the frame is
chosen first thereafter the size of motors and propellers are chosen. The frame dimensions used is 495 mm X 363
mm which is also depicted in fig 2.
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Fig. 2. Quadcopter frame dimensions.

The body frame is mainly divided into two parts: a base frame and the arms. The base frame is designed using
two parts of same size for the upper and lower base. Also, the size of four arms is equal. This frame design also
meant to anticipate the loose screws and bolts caused by vibrations when the quadcopter is flying. To design the
frame of quadcopter, materials such as plastic, carbon fiber, aluminium and wood can be used [7]. But in this case
Polyamide nylon 6 is used for the arms and E-glass fiber is used for the base frame of the quadcopter. The fig 3
clearly describes each part and the type of material used.

Fig. 3. Quadcopter body frame with different material.

Table 1 and Table 2 show the properties of polyamide nylon 6 and E-glass fiber respectively. The values of
mechanical properties of both the materials are taken form [4].

Table 1. Properties of polyamide nylon 6 (arm of frame)

Name of property Minimum value Maximum value
Yield strength 35MPa 40MPa
Poission ratio 0.38 0.40
Tensile strength 48 MPa 85 MPa
Density 1120 kg/m3 1140 kg/m3
Young’s modulus 2300 MPa 2500 MPa

Table 2. Properties of E-glass fiber (base plate)

 R. Singh et al. / Materials Today: Proceedings 22 (2020) 3320–3329 3323

Name of property Minimum value Maximum value

Bulk modulus 43 MPa 50 GPa

Poission ratio 0.21 0.23

Shear modulus 30 GPa 36 GPa

Density 2.55 mg/m3 2.6 mg/m3
Young’s modulus 72 GPa 85 GPa

The modelling of quadcopter frame is done in CATIA software [1]. The base frame and arms are designed
individually by taking the standard dimensions; afterwards all the components get assembled using the plane
inclination. The motors are drawn with outer dimensions only. The fig 4 depicts the arm of the quadcopter frame
designed in CATIA software.

Fig. 4. Mechanical model of arm of frame.

Fig 5 shows the complete model of quadcopter frame designed in CATIA software after assembling all the parts
together using line to line alignment tool.

Fig. 5. Mechanical model of assembled quadcopter frame.

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4. Quadcopter Structural Analysis

The analysis of the frame of the quadcopter is done to test the feasibility, rigidity and compatibility of frame. It
comprises of static and explicit/dynamic analysis. Rigidity of quadcopter body frame was analyzed considering the
equality between the vertical thrust produced by each motor and weight of the quadcopter during the flight time.
The thrust generated by each motor can be calculated [6] as shown below:

Thrust of each motor = P x D3 x RPM2 x 10-10 oz

Where D is the diameter of the propeller, P is the pitch of the propeller and RPM is the speed of the motor in
rotation per minute. The data taken for the analysis purpose is:
D = 8-inch, P = 4.5-inch, RPM = 11.1 x 1400 = 15540
After evaluating the eq.1, the calculated thrust of each motor is equal to 55.639 oz (15.47 N).
The rotating propeller affects the pressure change that is produced an upward thrust necessary to lift the
quadcopter to its four corners. The amount of thrust generated by motors at different speeds of quadcopter is
obtained [10]. The amount of resulting thrust can be used to calculate the rigidity or structural analysis of quadcopter
frame.

4.1. Static Analysis

The static and dynamic analysis of quadcopter frame is done using ANSYS software [9]. Firstly, the material
properties of polyamide nylon 6 and E-glass fiber are inserted afterwards a mesh is create which divides the
quadcopter frame into small segments as shown in fig 6.

Fig. 6. Mesh of the quadcopter frame.

The calculated thrust of each motor is applied on each four motors subtracting the weight of the quadcopter
divided into four equal parts in the opposite direction of the applied thrust by each motor as shown in figure 6.
Making the base of the frame ground (fixed) the static analysis is performed. The boundary conditions applied in
static analysis of frame is shown in the fig 7. A force equals to the thrust generated by the motor propeller set is
applied at the four corners and the base plate is made ground as shown in fig 7.
 R. Singh et al. / Materials Today: Proceedings 22 (2020) 3320–3329 3325

Fig. 7. Boundary conditions applied to the frame.

4.2. Dynamic Analysis

Dynamic analysis is done same as static analysis with different forces are applied for different dynamics. This is
obtained by observing the different velocity of the quadcopter during flight time at different interval of time and
distance. As mentioned before, the thrust generated by the motor depends on the type of motor and propeller used. In
propeller’s rotation process, the change direction of airflow around the propeller is associated with different force
based on the volume of air involved. This can be depicted by propeller pitch size and motor speed and with applied
voltage input. Firstly, the mesh is created as shown in the fig.8 after inserting the geometry and data. The mesh
divides the frame into small segments.

Fig.8. Mesh for the dynamic analysis.

Afterwards the boundary conditions are applied. In this case the thrust calculated above is applied at the four
corners and the overall weight of the quadcopter is applied in the opposite direction of the thrust of motor on the
base plate as shown by fig 9. Therefore the different velocity is measured for the different altitudes for the
quadcopter ascending upwards for the given motor propeller set which is inserted for obtaining the contours. The
different velocities at different altitudes are measured by taking a pillar and marking different altitudes measurement
3326 R. Singh et al. / Materials Today: Proceedings 22 (2020) 3320–3329

on it. Then quadcopter is ascended from the ground and time is noted for getting the specific altitudes, so distance
divides time give the velocity at different altitudes for a given motor rotor set. The mesh formed is not uniform or of
same shape so slight difference in contour can be observed. Fig 9 clearly depicts the boundary condition taken for
the explicit analysis of the quadcopter frame.

Fig. 9. Boundary condition of dynamic analysis.

5. Results And Discussions

The results of static and dynamic analysis are obtained by the above methodology is shown below:

5.1. Static Analysis

The total deformation contour and the equivalent stress contours are obtained by inserting the quadcopter
geometry in the ANSYS software as shown in fig 10 and fig 11. From fig 10 maximum deformation of 5.8439mm is
observed across the edges of the quadcopter arms shown by reddish yellow color and zero deformation is obtained at
the base plate as this plate is made ground or static with respect to the arms of the quadcopter. As shown in the fig 7
maximum stress of 6.2705 MPa is obtained at the inner edge of the arms of the quadcopter. As the base plate is
grounded, the stress on this is 1.3488e-10 MPa. The outer arms get deformed by the thrust of the motor and the stress
in obtained in the inner part off the arm as shown by the zoomed cross section of fig 11.
 R. Singh et al. / Materials Today: Proceedings 22 (2020) 3320–3329 3327

Fig. 10. Total deformation contour of static analysis.

Fig. 11. Equivalent stress contour of static analysis.

5.2. Dynamic Analysis

Fig 12 shows the total deformation contours obtained in the dynamic analysis. As shown in fig 12, the total
deformation of 0.0011674mm is obtained at center of the base plate. And maximum deformation of 0.00064853mm
is obtained at the four corners of the frame. As the material of inner plate is different from the arms of the
quadcopter so it has different deformation compared to the arm of the quadcopter. The inner circle of the base plate
shows maximum deformation signifies that the hollow base plate has to withstand a maximum deformation
compared to the other parts of the frame.
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Fig. 12. Total deformation contour of dynamic analysis.

Fig 13 shows the contours of equivalent stress on the frame of quadcopter and stress at different locations is
shown on the contour. As shown in fig 13, maximum stress of 0.22924 MPa during dynamic analysis is obtained at
the outer edge of the arms of the frame shown by the zoomed cross section with shades.And minimum stress of zero
value is obtained at the base plate of the frame of the quadcopter.

Fig. 13. Equivalent stress contour of dynamic analysis.

 R. Singh et al. / Materials Today: Proceedings 22 (2020) 3320–3329 3329

6. Conclusion

By considering all the above results for both static and dynamic analysis, the frame material, motor KVA and the
propeller size all the three factors gives different contour plots. The stress and deformation on the frame is
proportional to the thrust generated by the motors and the geometry of the frame. These contours help us designing
the different frame of specific material which can withstand the different variable conditions and specific usage. The
material and data taken in this analysis is compatible with the data and gives accurate results and can be chosen for
making the quadcopter for the agricultural, surveillance and other purposes. This signifies that frame can withstand
the maximum stress applied by the motor propeller set which we have chosen for the analysis purpose.

Acknowledgements

Authors would like to thank Department of Electrical and Electronics Engineering and Department of Mechanical
Engineering of National Institute of Technology Delhi for providing the facilities to carry out this project work.

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