ENGG1300-Practical-Work-Report
File description: The final report for the ENGG1300 Practical Work.
Document status: FIN
Last modified: 2026-09-11 21:12 HKT
ENGG1300C, Gp. C9, 2024/25-Spring
Final Report for Practical Work
Final Report for Practical Work of the Course
ENGG1300 of Group C9
Author A
1
, Author B
2
, Author C
3
, Author D
4
, Zhan Ho Jacob Shing
5
, Author F
6
, Author G
7
Abstract
This report aims to summarise the practical work done for the course ENGG1300 – Fundamental Mechanics
in the second semester of the academic year 2024/25 by Group C9. This report introduces the problem
presented to the group in the practical work, the process of drafting and verifying, and the methodology of
the solution, the theorems and principles on which the solution is based, the results and quantitative analysis
of the results, and the conclusion and reflection on the practical work.
*Authors are listed in alphabetical order by surname.
1
Bachelor of Engineering (BEng), 3036******
2
Bachelor of Engineering (BEng), 3036******
3
Bachelor of Engineering (BEng), 3036******
4
Bachelor of Engineering (BEng), 3036******
5
Bachelor of Engineering (BEng), 3036******
6
Bachelor of Engineering (BEng), 3036******
7
Bachelor of Engineering (BEng), 3036******
Contents
Introduction 1
1 Theorems and Principles 1
1.1 Buckling and Euler’s Load . . . . . . . . . . . . . . 1
1.2 Radius of Gyration . . . . . . . . . . . . . . . . . . . . 2
2 Designing and Drafting 2
2.1 Major Members . . . . . . . . . . . . . . . . . . . . . . 2
Pipe Configuration • Paper-to-Paper Connection Structure
2.2 Supporting Members . . . . . . . . . . . . . . . . . . 2
2.3 Restraining Piece . . . . . . . . . . . . . . . . . . . . . 3
3 First Trial 3
3.1 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2 Rationale of Failure . . . . . . . . . . . . . . . . . . . 3
Low Density of the Major Members • Presence of Weak Points
at Paper-to-Tape Junctions • Imbalance of Load Distribution
Due to Mismatched Lengths of the Slanted Members
3.3 Measures Taken for Improvement . . . . . . . . . 3
Rolling the Members with Tools to Increase Density and Avoid
Defects • Apply Adhesive Tapes Thoroughly and Effectively
4 Final Trial 4
4.1 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.2 Reflection and Possible Improvements . . . . . 4
5 Conclusion 5
Acknowledgments 5
References 5
Introduction
The group was presented a problem to design and realise a
structure using only ordinary newspapers and transparent
plastic adhesive tapes. The problem further specified that
the said structure shall observe the following conditions:
1.
The structure must stand on its own without any ex-
ternal support.
2.
The height of the structure must be between
780
mm
and 800 mm.
3. The structure must not weight more than 1 kg.
4.
The structure shall be able to bear at least
500
N
of load without excessive deformation when being
compressed by two wooden plates of
480
mm
× 480
mm × 10 mm.
1. Theorems and Principles
In preparation for the practical work, and in the process of
performing analysis, the group consulted various materials
for building their knowledge and establishing a basic under-
standing of the principles and theorems that may be useful
for the practical work.
The theorems and principles that were used in the prac-
tical work are listed in this section. For avoiding repetitive
contents, only those theorems and principles that are beyond
the scope of the course ENGG1300 are listed.
1.1 Buckling and Euler’s Load
It was introduced that under compressive load, sudden large
deformation may occur in the member, which is termed as
buckling. To quantitaively describe the boundary load at
which buckling occurs, Euler’s Load is introduced [
1
]. It
is given by:
P
cr
= π
2
EI
L
2
(1)
where
P
cr
is the Euler’s critical load,
E
is the Young’s mod-
ulus of the material,
I
is the moment of inertia of the cross-
section, and L is the length of the member.
The greater the critical load, the more stable the member
is. By inspection, it is trivial to see that to obtain a greater
Page 1 of 5
Final Report for Practical Work of the Course ENGG1300 of Group C9 — 2/5
critical load, it is desirable to have a greater moment of
inertia I and a smaller length L .
1.2 Radius of Gyration
The radius of gyration
k
is derived from the moment of
inertia I of a cross-section [2]. It is given by:
k =
I
A
(2)
where A is the cross-sectional area of the member.
Assuming the crosee-sectional area
A
is constant, by the
conclusion of the previous theorem, a more stable member
will have a greater moment of inertia
I
, and thus a greater
radius of gyration
k
. It is therefore concluded that a member
with greater radius of gyration k is more stable.
2. Designing and Drafting
In the designing and drafting phase, the group has estab-
lished a basic model, which is composed of three compo-
nents: the major members, the supporting members, and the
restraining piece. These three components have different
functions and are carefully designed to have different shapes
and methods of production. Figure 1 shows an overview of
the model.
Figure 1. Overview of the model. The major members are
shown in orange, the supporting members are shown in
green, and the restraining piece is shown in red.
2.1 Major Members
The major members are one straight column erected verti-
cally from the ground, and three slanted columns connecting
the ground and the top of the vertical column. The points
where the slanted columns contact the ground are the ver-
tices of an equilateral triangle whose circumcenter is the
point where the vertical column contacts the ground.
The major members are the longest members of the
model and bear the most load. Therefore, they become
unstable as the length increases as shown in Equation 1.
2.1.1 Pipe Configuration
To address this issue, the major members were fabricated by
combining three densly rolled newspaper pipes (termed as
the tri-pipe configuration, Figure 2b) as opposed to using a
single pipe (termed as the mono-pipe configuration, Figure
2a). It is easy to proove that the tri-pipe configuration is
more effective than the mono-pipe configuration.
(a) Mono-pipe
configuration
(b) Tri-pipe
configuration
Figure 2. Cross-sectional view of the mono-pipe
configuration and the tri-pipe configuration.
Assume that both configurations have the same cross-
sectional area
A
, and that the members are solid cylinders,
each pipe of the tri-pipe configuration has a diameter
d
and
the pipe of the mono-pipe configuration has a diameter
D
.
We can express D in terms of d as D =
√
3d.
By calculation, we obtain the moment of inertia
I
of
both configurations as
I
tri
=
19
64
π d
4
> I
mono
=
9
64
π d
4
[
2
]. By
adopting the tri-pipe configuration, the moment of inertia
is increased by approximately
111%
, which is a significant
improvement. This shows that the tri-pipe configuration has
a larger critical load.
Furthermore, by using Equation 2, we obtain the radii
of gyration:
k
tri
=
√
57
12
d > k
mono
=
√
3
4
d
.
k
tri
is approxi-
mately
45%
larger than
k
mono
. This shows that the tri-pipe
configuration is more resistant to buckling and compressive
stress.
2.1.2 Paper-to-Paper Connection Structure
After measurement, it was found that the longest side of one
piece of newspaper is approximately
600
mm. It is therefore
impossible to fabricate a pipe with one single continuous
piece of paper, and joining two pieces of paper is inevitable.
Two solutions were proposed to join pieces of paper for
extending the length:
1.
By overlapping pieces of newspapers alternatively;
or
2.
By placing two pieces of newspapers side-by-side
and fixing them together with adhesive tape.
By comparison as illustrated in Table 1, the overlap-
ping method was chosen to form the pipes as it is more
performant on the assessed aspects.
2.2 Supporting Members
The supporting members connect the adjacent slanted major
members. They are supposed to hold major members in
place through the tensile force generated by the strong and
long paper fibres.
Since they do not bear compressive load but only tensile
load, buckling was not a concern. Therefore, the supporting
members were simply made of a single pipe.
Page 2 of 5
Final Report for Practical Work of the Course ENGG1300 of Group C9 — 3/5
Table 1. Compaison of the overlapping and side-by-side connection methods.
Aspect Overlapping Side-by-side
Load Distribution Across all layers via friction and interlocking Concentrated at the joint
Strength ∝ number of layers × strength of one layer ∝ adhesive shear strength
Stiffness High due to composite action Low due to tape not structurally integrated
2.3 Restraining Piece
Since the major members are slanted, it was projected that
the vertical compressive load would decompose into down-
ward vertical component and horizontal component directed
away from the centre at the end of the slanted members.
When the horizontal component is larger than the friction
between the major members and the ground, the members
would start to slide away from the centre, which would
lead to most of the load being redistributed to the central
member.
To restrain the horizontal movements of the members,
the group has designed a restraining piece. The piece was
made of several layers of continuous newspapers folded
into a belt-like shape, which was then wrapped around the
base.
Due to its continuous nature, the full potential of the
paper fibres could be utilised to provide tensile strength.
It was expected that when the members start to slide, the
restraining piece would be able to counteract with its tensile
strength.
3. First Trial
The model for the first trial was built with the following
specifications:
1. Weight and Height: Within the limits.
2.
Newspaper Used: Mainly the Sing Tao Daily (
星島
日報).
3. Adhesive Tape Used: Scotch Magic Tape (3M).
4.
Design: The supporting members did not observe the
design as described in section 2.2. However, those
members did not have significant impact on the anal-
ysis of the model.
The model is shown in Figure 3a.
3.1 Results
The first model failed to withstand a minimum load of
500 N
. The model was able to withstand a load of
480 N
before deformation occurred. It was observed that buckling
occurred at the major members at a short instant after the
load was applied (as shown in Figure 3b). Of all the mem-
bers, the three external slanted members were the first to
buckle, while the central vertical member experienced the
most deformation.
3.2 Rationale of Failure
After inspection of the failed model, the group has identified
three major reasons that contributed to the failure of the
model.
3.2.1 Low Density of the Major Members
All of the major members in the model were fabricated with-
out aid of any tools. The newspaper pipes were rolled by
hand, leaving large gaps between the layers of newspapers.
This resulted in a low density of the major members.
To quantitatively analyse this issue, the gap-interleaving
members can be approximated as a hollow cylinder of inner
radius
r
and outer radius
R
and compared with a solid cylin-
der of radius
R
. The moments of inertia of the two models
are
I
hollow
=
π
64
(D
4
−d
4
)
and
I
solid
=
π
4
D
4
. It is trivial to see
that
I
hollow
< I
solid
. By Equation 1, the critical load of the
hollow cylinder is less than that of the solid cylinder. This
shows that the hollow cylinder is more prone to buckling.
Furthermore, during fabrication, the newspapers might
have been rolled unevenly, resulting in folds and wrinkles
on the surface of the pipes. This further reduce the stability
of the major members.
3.2.2
Presence of Weak Points at Paper-to-Tape Junc-
tions
While applying the adhesive tape on the pipes, the surfaces
of the pipes were not thoroughly covered, resulting in sur-
faces that were exposed to air. This led to inconsistent
surface stiffness as surfaces with adhesive tapes are stiffer
than those without. When under compressive pressure, the
joints at which surfaces with discontinuous stiffness meet
are prone to buckling.
3.2.3
Imbalance of Load Distribution Due to Mismatched
Lengths of the Slanted Members
The group was not rigorous in measuring the lengths of the
slanted members. Prior to the first trial, the group has no-
ticed that the structure was unable to support itself evenly on
all columns, and that one of the slanted members remained
not in contact with the ground. This resulted in an imbal-
ance of load distribution. During compression, the stress
was concentrated on the central member and the slanted
members that were in contact with the ground, while the re-
maining member acted as a Zero Force Member. As a result,
some of the members were subjected to stress that exceeded
the designed limit and buckled, which is consistent with the
observation.
3.3 Measures Taken for Improvement
In order to address the issues identified in the first trial,
the group has taken the following measures to improve the
model in fabrication of the model for the final trial.
3.3.1
Rolling the Members with Tools to Increase Den-
sity and Avoid Defects
The group has used thin cylindrical wooden rods to assist
in rolling the newspapers into pipes. The rods were placed
on the newspapers while rolling, such that the newspapers
Page 3 of 5
Final Report for Practical Work of the Course ENGG1300 of Group C9 — 4/5
(a) Before (b) Immediately after failure
Figure 3. The model before and after the first trial.
(a) Before (b) Immediately after failure
Figure 4. The model before and after the final trial.
could bind tightly and uniformly, reducing gaps between
layers and wrinkles on the surface. The rod was then re-
moved after the pipe was rolled. This method streamlined
pipe production and improved the strength of the major
members.
3.3.2
Apply Adhesive Tapes Thoroughly and Effectively
The group has carefully applied the adhesive tapes on the
pipes to ensure that the entire surface of the pipes were
covered evenly with tapes. This is projected to increase the
stiffness and uniformity of the surfaces.
In addition, the group has also applied more tapes at the
top and bottom of the pipes as these are the areas that are
subjected to the most stress and need to be reinforced.
4. Final Trial
The model for the final trial was built with the same spec-
ifications as the first trial, except that the design of the
supporting members was changed to observe the design as
described in section 2.2. The model is shown in Figure 4a.
4.1 Results
In the final trial, the model was able to withstand a load of
767 N
, which satisfied the requirement of the practical work
and was a significant improvement from the first trial.
As opposed to the first trial, buckling occurred almost
simultaneously at all members when the critical load was
approached. This displayed that the load was distributed uni-
formly throughout the model, showing that the alterations
made to the design was effective.
4.2 Reflection and Possible Improvements
Despite the success of the final trial, the group has identified
possibility for further improvements.
From the deformed model, it was observed that buckling
started but did not progress significantly until the support-
ing members dislocated from the major members. It has
shown that the supporting members were indeed effective
in providing stability and the reinforcement of which could
have further increased the critical load.
Additionally, the group has observed that the restraining
piece that was expected to restrain horizontal movements
of the major members almost bore no load during both
trials. This has shown that the group has overestimated the
magnitude of the horizontal movements and underestimated
the friction between the major members and the ground.
Much of the weight could have been saved or diverted to
other components of the model if the restraining piece was
not used.
Page 4 of 5
Final Report for Practical Work of the Course ENGG1300 of Group C9 — 5/5
5. Conclusion
This practical work has encouraged the group to consolidate
and apply the knowledge learned in class, and to explore fur-
ther beyond the scope of the course. THe group has gained
a deeper understanding of the principles and theorems in
the field of structural and material mechanics. The group
has also earned precious experience through the process of
designing, trial-and-error, observing, and reflecting. The
practical work has also offered an opportunity for the group
to communicate effectively.
Acknowledgments
We would like to express our profound gratitude to the
course instructors and teaching assistants for providing guid-
ance and support upon consultation.
We would also like to thank all the members of Group
C9 for their efforts and contribution to the practical work.
We would like to thank the library of the University of
Hong Kong for providing an extensive collection of materi-
als for reference and research.
Finally, we would like to thank the authors Mathias
Legrand and Vel for providing this professional L
A
T
E
X template.
References
[1]
R. C. Coates. Structural Analysis. Taylor & Francis
Group, 2018.
[2]
William F. Riley, Leroy D. Sturges, and Don H. Morris.
Mechanics of materials. John Wiley, Hoboken, N.J, 6th
edition, 2007.
Page 5 of 5
Note
The names and student IDs of the authors except for the owner of this repository have been hidden for privacy reasons.
The group has received a score of 88.5% for the practical work component of the course.
Update to the document
This document is the report submitted for the practical work component of the course ENGG1300. It will not be updated since the document is supposed to be uploaded as-is.
See also
-
CCCH9044-Individual-Essay
The 3000-word individual essay for the course CCCH9044.
-
CCGL9042-Question-Bank
The question bank for CCGL9042 in-class quizzes.
-
CCHU9094-Essay
Read the student submission of the essay to CCHU9094. This work has been graded A.
-
CCST9064-Video-Essay
The final video essay submitted for CCST9064 group project. Python code for Manim included.
-
COMP1110-Project
The GitHub repository of the group project.
-
COMP1110-Project-IndividualReport_JacobShing
Individual report for COMP1110 (25/26 Spring) by Jacob Shing.