MECH ENG 3111 - Acoustics and Vibrations

North Terrace Campus - Semester 2 - 2024

Acoustics and vibrations are one of the core pillars of the mechanical engineering discipline, with applications that range from civil structures, architectural and environmental systems, and all forms of mechanical systems including transport vehicles and aircraft. This course introduces the fundamental concepts of acoustics, including characterisation and quantification of sound sources, exposure to noise, and noise control, mitigation, and psychoacoustics. Vibration systems are covered in detail from lumped parameter models through to continuous and multi-degree of freedom systems. Design of vibration control devices, such as vibration isolators and vibration absorbers, is also considered. A strong emphasis is placed on frequency response characteristics for both acoustics and vibration applications, including practical exposure to spectral analysis and its application to predictive maintenance using machine condition monitoring.

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Course Details

Course Code	MECH ENG 3111
Course	Acoustics and Vibrations
Coordinating Unit	Mechanical Engineering
Term	Semester 2
Level	Undergraduate
Location/s	North Terrace Campus
Units	3
Contact	Up to 6 hrs per week
Available for Study Abroad and Exchange	Y
Prerequisites	MECH ENG 1007, MECH ENG 2019
Incompatible	MECH ENG 3028, MECH ENG 7047
Assessment	Quizzes, assignments, practical, exam

Course Staff

Course Coordinator: Professor Anthony Zander

Course Timetable

The full timetable of all activities for this course can be accessed from Course Planner.

Course Learning Outcomes

On successful completion of this course students will be able to:

1	Understand the fundamentals of acoustics;
2	Understand basic noise control systems;
3	Be able to assess occupational and environmental noise problems;
4	Discuss the principles of vibrations, including concepts of modes and natural frequencies, and the influence of mass, stiffness and damping on the motion of vibratory systems;
5	Demonstrate how to estimate system parameters and measure the damping of simple vibratory systems;
6	Explain the principles controlling basic vibration systems including forced vibratory systems, vibration isolation systems, and vibration absorbers;
7	Explain the modes and natural frequencies of simple, idealised continuous systems;
8	Explain the fundamentals of modelling complex continuous systems with discrete lumped-masses and springs;
9	Understand the fundamentals of signal processing/spectral analysis;
10	Understand the condition of a machine by analysing its vibration signature history to predict its performance and to diagnose faults from knowledge of characteristic "fault" vibration signatures.

The above course learning outcomes are aligned with the Engineers Australia Entry to Practice Competency Standard for the Professional Engineer. The course develops the following EA Elements of Competency to levels of introductory (A), intermediate (B), advanced (C):

1.1	1.2	1.3	1.4	1.5	1.6	2.1	2.2	2.3	2.4	3.1	3.2	3.3	3.4	3.5	3.6
B	B	C	C	C	B	C	C	C	—	B	B	—	C	B	A

University Graduate Attributes

This course will provide students with an opportunity to develop the Graduate Attribute(s) specified below:

University Graduate Attribute	Course Learning Outcome(s)
Attribute 1: Deep discipline knowledge and intellectual breadth Graduates have comprehensive knowledge and understanding of their subject area, the ability to engage with different traditions of thought, and the ability to apply their knowledge in practice including in multi-disciplinary or multi-professional contexts.	1-10
Attribute 2: Creative and critical thinking, and problem solving Graduates are effective problems-solvers, able to apply critical, creative and evidence-based thinking to conceive innovative responses to future challenges.	1-10
Attribute 3: Teamwork and communication skills Graduates convey ideas and information effectively to a range of audiences for a variety of purposes and contribute in a positive and collaborative manner to achieving common goals.	4-8
Attribute 7: Digital capabilities Graduates are well prepared for living, learning and working in a digital society.	1-10

Learning Resources

Required Resources

Course Notes and associated resources available on MyUni.

Recommended Resources

Inman, D.J., Engineering Vibration, Pearson, Fourth Edition, 2014; or
Thompson W.T., 1993, Theory of Vibration with Applications, Fourth Edition, Stanley-Thornes.

Bies and Hansen "Engineering Noise Control: Theory and Practice", CRC Press.

Online Learning

Significant links to online resources available on MyUni.
Learning & Teaching Activities

Learning & Teaching Modes

Online lectures supported by tutorials, a computer lab-based workshop and a practical.

All lectures will be delivered online. These online lectures will be complemented by learning activities including a computer lab-based workshop, quizzes, assignments and a face-to-face practical. Lecturers will also be available weekly at designated times for tutorials and consulting in person or via Zoom.

Workload

The information below is provided as a guide to assist students in engaging appropriately with the course requirements.

As per university recommendations, it is expected that students spend 48hrs/week during teaching periods, and that a 3 unit course has a minimum workload of 150 hours regardless of the length of the course. Additional time may need to be spent acquiring assumed knowledge, working on assessment during non-teaching periods, and preparing for and attending examinations.

Learning Activities Summary

Below is a breakdown of the scheduled learning activities for this course:

Acoustics

Fundamentals of Acoustics
Amplitude, frequency, wavelength, speed of sound.
Logarithmic scale, octave and 1/3rd octave bands.
Sound Pressure Level, addition and subtraction of pressure and SPLs.
Noise reduction addition.
Beating.
Sound Intensity, Sound Power, Directivity, SPL at a distance from a sound power source.
Subjective assessment of change in SPL & A-weighting.
Instrumentation used in acoustics.
Psychoacoustics
The A-weighting scale.
The subjective perception of loudness.
The concept of masking noise and the limitation of human hearing.
The concept of critical bands.
How jury testing can be used for product evaluation.
General Noise Control Techniques
Basics of Acoustics.
Vibro-acoustic noise control.
Air-borne noise control.
Liquid-borne noise control.
Building acoustics.
Silencers and mufflers.
Occupational and Environmental Noise
Noise induced and age related hearing loss.
Estimation of noise exposure.
Noise exposure trading rules.
Metrics used to describe noise spectra in offices, such as Room Criteria.
Community noise level criteria.

Vibrations

Free vibration of single degree-of-freedom systems (2 lectures)
Forced vibrations (3 lectures)
Damped vibrations (2 lectures)
Vibration isolation (3 lectures)
Multi-degree of freedom systems (4 lectures)
Vibration of continuous systems (2 lectures)
Determination of natural frequencies and mode shapes (5 lectures)
Practical

Spectral Analysis

Spectral analyis including the fast fourier transform, windowing, averaging, discretisation and frequency resolution.
Overview of maintenance methods, machine heath indicators and standards, characteristic machine "fault" signatures for a range of mechanical faults including imbalance, misalignment, gear mesh problems, and rolling element bearing failures.
Computer lab-based workshop on spectral analysis using MATLAB (3 x 2 hour sessions)

The University's policy on Assessment for Coursework Programs is based on the following four principles:

Assessment must encourage and reinforce learning.
Assessment must enable robust and fair judgements about student performance.
Assessment practices must be fair and equitable to students and give them the opportunity to demonstrate what they have learned.
Assessment must maintain academic standards.

Assessment Summary

Assessment Task	Task Type	Due (week)*	Weighting	Learning Outcome
Acoustics quizzes	Formative	Week 6	3%	1,2,3
Acoustics assignment	Summative	Week 6	9%	1,2,3
Vibrations quizzes	Formative	Weeks 6, 9	5%	4,5,6,7,8
Vibrations assignments	Summative	Weeks 8, 10	10%	4,5,6,7,8
Practical	Summative	14 days after session	5%	4,5,6,7,8
Signal processing quiz	Formative	Week 12	4%	9
Signal processing assignment	Summative	Week 12	4%	9
Exam	Summative	Exam period	60%	1-9

* The specific due date for assessment tasks will be available on MyUni.

Assessment Related Requirements

The practical is a compulsory hurdle requirement. To pass the course each student must:

attend the practical;
submit a group practical report; and
obtain at least 50% of the total practical mark.

Assessment Detail

Acoustics (weighted at 30% of overall course mark)

The acoustics assignment is submitted electronically and comprises 30% of the Acoustics component mark, with the acoustics quizzes worth 10% of the Acoustics component mark The exam comprises 60% of the Acoustics component mark.

Vibrations (weighted at 50% of overall course mark)

The Vibrations assessment comprises two quizzes (10% of Vibrations component in total), two assignments submitted electronically (20% of Vibrations component in total), and the practical worth 10% of the Vibrations component mark. The exam comprises 60% of the Vibrations component mark.

Spectral Analysis (weighted at 20% of overall course mark)

The assessment comprises one quiz (20% of Spectral Analysis component in total), one assignment (20% of Spectral Analysis component in total), and the exam which comprises 60% of the Spectral Analysis component mark.

Variations in the assessment scheme are negotiable only on medical or compassionate grounds or extenuating circumstances.

Submission

All quizzes, assignments and practical reports must be submitted online via MyUni/Mobius as per instructions for each assessment. Late submissions are not possible as Mobius/MyUni automatically prevents submission after the due time on the due date, unless an extension has been granted and implemented in Mobius/MyUni by the Course Coordinator.

Extensions for assignments will only be given in exceptional circumstances and a case for this with supporting documentation can
be made in writing via email to the Course Coordinator. For a 3 calendar day extension, the Course Coordinator must receive an email at least one business day before the assessment deadline; for longer extensions a completed Application for Assessment Extension form (https://www.adelaide.edu.au/student/exams/assessment-applications/assessment-extension) must be completed. There are only three grounds for which an extension can be granted: Medical Circumstances, Compassionate Circumstances and/or Extenuating Circumstances. Course Coordinators cannot grant extensions based on balancing student workloads.

There will be no opportunities for re-submission of work of unacceptable standard.

Due to the large size of the class feedback on assignments will be limited to in-class discussion resulting from questions from students and individual automatic feedback through Mobius/MyUni.

Course Grading

Grades for your performance in this course will be awarded in accordance with the following scheme:

M10 (Coursework Mark Scheme)
Grade	Mark	Description
FNS		Fail No Submission
F	1-49	Fail
P	50-64	Pass
C	65-74	Credit
D	75-84	Distinction
HD	85-100	High Distinction
CN		Continuing
NFE		No Formal Examination
RP		Result Pending

Further details of the grades/results can be obtained from Examinations.

Grade Descriptors are available which provide a general guide to the standard of work that is expected at each grade level. More information at Assessment for Coursework Programs.

Final results for this course will be made available through Access Adelaide.

Student Feedback

The University places a high priority on approaches to learning and teaching that enhance the student experience. Feedback is sought from students in a variety of ways including on-going engagement with staff, the use of online discussion boards and the use of Student Experience of Learning and Teaching (SELT) surveys as well as GOS surveys and Program reviews.

SELTs are an important source of information to inform individual teaching practice, decisions about teaching duties, and course and program curriculum design. They enable the University to assess how effectively its learning environments and teaching practices facilitate student engagement and learning outcomes. Under the current SELT Policy (http://www.adelaide.edu.au/policies/101/) course SELTs are mandated and must be conducted at the conclusion of each term/semester/trimester for every course offering. Feedback on issues raised through course SELT surveys is made available to enrolled students through various resources (e.g. MyUni). In addition aggregated course SELT data is available.
Student Support
Policies & Guidelines
This section contains links to relevant assessment-related policies and guidelines - all university policies.
Fraud Awareness

Students are reminded that in order to maintain the academic integrity of all programs and courses, the university has a zero-tolerance approach to students offering money or significant value goods or services to any staff member who is involved in their teaching or assessment. Students offering lecturers or tutors or professional staff anything more than a small token of appreciation is totally unacceptable, in any circumstances. Staff members are obliged to report all such incidents to their supervisor/manager, who will refer them for action under the university's student’s disciplinary procedures.

The University of Adelaide is committed to regular reviews of the courses and programs it offers to students. The University of Adelaide therefore reserves the right to discontinue or vary programs and courses without notice. Please read the important information contained in the disclaimer.

Authorised by:	Deputy Vice-Chancellor and Vice-President (Academic)
Maintained by:	Course Outlines Administrator