The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MAE
HKUST
Design of Experiments
MECH3830
1/3
3.1 Overview
Experiments are performed by people in all aspects of life.
The basic reason for running an experiment is to find out some information which
is not known.
Experiments are designed to draw inference
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MAE
HKUST
VIBRATION MEASUREMENTS
Dailylife examples
MECH3830
1/8
MAE
HKUST
VIBRATION MEASUREMENTS
MECH3830
2/8
MAE
HKUST
VIBRATION MEASUREMENTS
MECH3830
3/8
10.1 Free Vibration
Vibration without external excitation such as force or motion
(but with some
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
Solutions
1.
(a) Because the whole Platinum thin film has a uniform temperature, the two junctions (PlatinumIron and PlatinumAlumel) have a same temperature T. According to thermocouple law 3 (manual
page 90), the net emf of the circuit is the same as if
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MECH3830 Homework#1
(Due day of return: submit in the class on 3 March 2017)
1. Express the following numbers rounded to 3 Significant Figures:
(A) Sidereal Year = 365.25636 mean solar days.
(B) Density of water (at 4oC) = 0.999972 g/cm3.
(C) Speed of lig
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MECH3830 Homework#3
(Due day of return: 5 May 2017)
1. A piezoelectric pressure transducer is used to measure steady state water pressure in a water
channel as shown in Fig. 1.
P
Amplifier (x100)
U
u
Fig. 1 Pressure transducer measurements
Ideally, the pr
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MECH3830 Homework
Solutions for Homework#1
1.
A.
B.
C.
D.
365
1.00
3.00108
5.23105
A.
B.
C.
D.
E.
F.
3
3
4
4
4
2
A.
B.
C.
D.
E.
20.6
7.0
5.925102 or 529.5
3.446
1.7102 or 0.017
2.
3.
4.
a. B has higher accuracy, because the difference between the measur
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MECH283 Qiuz (Fall 2002/2003)
Answer Key
1. (a) Z(X1, Y4)=Z(X1, Y3)+Z(X3, Y4)Z(X3, Y3)
Z ( X 1 , Y3 ) Z ( X 3 , Y4 ) Z ( X 3 , Y3 )
(b) Z ( X 1 , Y4 ) = (1 + X 12Y42 )
+
2 2
2 2
1
X
Y
1
X
Y
1 + X 32Y32
+
+
1 3
3 4
2.
1)
a) p = 0.1bar
b) 0.5bar or 5% of
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
3. Theory
Viscoelasticity describes the properties of liquids to explain both viscous and elastic response to an
applied stress and is commonly observed in melts of polymers, concentrated polymer solutions and
concentrated colloidal dispersions. Viscoelas
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
Department of Mechanical Engineering
Hong Kong University of Science and Technology
Clear Water Bay, Kowloon, Hong Kong
MECH 3830
Laboratory
Experiment #3 Flow through a Venturi Meter
Lab Report
Submitted by: CHAN, Ka Man
(20125131)
CHENG, Cheuk Fung
(201
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
4. Results and Discussion
Figs. 1 shows the wave form where the function generator output have set to zero and have
acquired 2500 samples of data to generated a DC signal. It performed the calibration of the
following measurements. The result shows that t
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
Department of Mechanical Engineering
Hong Kong University of Science and Technology
Clear Water Bay, Kowloon, Hong Kong
MECH 3830
Laboratory
Experiment #2 Vibration Measurements
Lab Report
Submitted by: CHAN, Ka Man
(20125131)
CHENG, Cheuk Fung (20123303)
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
Abstract
This experiment is done to clarify the relationship between stress and different amount of load and
mechanical properties. Strains are measured on an acrylic plate with a hole at the center which has
been stretched with different uniaxial forces
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MECH283 Quiz (Fall 2002/2003)
Student Name:_ ID: _ Date: _
1. A 3D surface (the surface hight, z) is described as:
10
10
Z ( X , Y ) = k (a1 X 2 + a 2 X + a 3 ) + (a 4Y 2 + a5Y + a 6 )
k
k =1
(1)
where a16 are unknowns.
Measurements are performed follow
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
1.Abstract
2.Introuction
The main goal of the experiment is to study the thermodynamics of the vapor compression cycle,
commonly utilized in the refrigeration process, under variable loads and speeds. Through this
experiment, the best operating condition
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MECH283 Review Questions (Fall 2002/2003)
Some of the answer Key
Z ( X 1 , Y3 )Z ( X 3 , Y1 )
Z ( X 3 , Y3 )
Z ( X 1 , Y3 )Z ( X 3 , Y1 )
(b) Z ( X 1 ,Y1 ) =
Z ( X 3 , Y3 )
2. (a) Z ( X 1 ,Y1 ) =
5. (a) Accuracy depends on the bias of u, i.e. u which is 0
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MECH283 Review Questions
1. A 3D surface is measured by using a calliper. The response of the system (the surface hight, z)
can be described as:
2
2
z e ax bx cy dy sin ex 1 cos fy 1
where af are unknown constants.
Measurements are performed following th
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MAE
HKUST
FLOW MEASUREMENTS
6.1 Local Flow Velocity, Magnitude and Direction
Flow Visualization
MECH3830
1/6
MAE
HKUST
FLOW MEASUREMENTS
Velocity Probes
HotWire Anemometry
MECH3830
2/6
MAE
HKUST
FLOW MEASUREMENTS
Laser Doppler Anemometry
MECH3830
3/6
M
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MAE
HKUST
Analysis of Experimental Data
MECH3830
1/5
Some form of analysis must be performed on all
experimental data.
A few mathematical tools have been developed for data analysis:
Least Squares Method
Error and Uncertainty Analysis
MAE
HKUST
5.1
Anal
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MAE
HKUST
Basic Concepts and Terms
MECH3830
1/2
2.1 Dimensions, Units & Standards
A dimension is a physical variable used to specify the behavior or the
state of a particular system. For example, the length of a rod is a
dimension describing its size or t
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MAE
HKUST
4.1
Data Acquisition
MECH3830
1/4
Basic Data Acquisition System
Objective:
Collect data, process them in a desired fashion, and record the results in a form
suitable for storage, presentation, or additional subsequent processing.
The essential e
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MAE
HKUST
MECH3830
Laboratory
(Spring Semester 2015/2016)
Prof. Dr. Ing. Huihe Qiu
Department of Mechanical and Aerospace Engineering
The Hong Kong University of Science and Technology
Clear Water Bay, Kowloon
Hong Kong
2016
MECH3830
1/1
MAE
HKUST
Introd
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MECH3830 Homework#1
(Due day of return: 4 March. 2016)
1. Express the following numbers rounded to 3 Significant Figures:
(A) Sidereal Year = 365.25636 mean solar days.
(B) Density of water (at 4oC) = 0.999972 g/cm3.
(C) Speed of light (vacuum)= 2.9979245
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MECH3830 Homework#2
(Due day of return: During the Lecture on 18 March 2016)
1. A piezoelectric pressure transducer is used to measure steady state water pressure in a
water channel as shown in Fig. 1.
P
Amplifier (x100)
U
u
Fig. 1 Pressure transducer mea
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MECH3830 Homework#1
(Due day of return: 4 March. 2016)
1. Express the following numbers rounded to 3 Significant Figures:
(A) Sidereal Year = 365.25636 mean solar days.
(B) Density of water (at 4oC) = 0.999972 g/cm3.
(C) Speed of light (vacuum)= 2.9979245
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
Brief Solution for Review Questions of MECH283
1. The Function Z can be expressed as the following form:
Since af are constants, so the equation can be written as:
Z ( x, y ) F ( X )G (Y ) where
F ( X ) e ( ax
2
bx )
(1 sin ex )
and
G (Y ) e cy
2
dy
(1
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MECH3830 Homework#3 (Spring 2015/2016)
(This is voluntary homework. No Need to Submit; The Solution will be posted on May 16)
1.
A stable rotation speed of the disk plates in a high speed
and high capacity harddisk is important. The disk rotating
is power
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MECH3830
(Review Questions)
1. A 3D surface is measured by using a calliper. The response of the system (the surface hight, z)
can be described as:
2
2
z eax bx cy dy sinex 1 cos fy 1
where af are unknown constants.
Measurements are performed following t
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
Solutions for Homework#2
1. 1)
a) P a U U aU aU
Because U has a mean value of 0.05V,
The accuracy of measurements will be:
P = aU = 10 * 0.05 = 0.5 bar
Therefore, the measurement accuracy is 0.5bar
b) The precision of the measurements is determined by the
The Hong Kong University of Science and Technology
Laboratory
MECH 3830

Spring 2016
MAE
HKUST
PinJointed Frame With Buckling
Member
MECH3830
1/9
The critical buckling load for a pinjointed member under
compression is given by:
where
L = member length
I = second moment of area based on the crosssection of the member
E = modulus of elas