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Assessment Brief 1 Student Name/ID Number Course BTEC HNC in General Engineering Unit Number and Title 8: Mechanical Principles Academic Year 2020/21 Unit Tutor Philip Arnold Assignment Title Number 1. Bending moments & Stress Modelling in a variety of Beams, Tubes, Bars caused by perpendicular loads and Torsion. Issue Date 18th January 2021 Submission Date 18th February 2021 IV Name & Date Allocation of time to complete assignment Parts 1, 2, 3, 5, as well as additional analysis needed for part 2 and report needed for part 5 which while normally done outside of class. Estimated time for completion of work 20 Hours Submission Format This is a problem based assessment. To evidence that you have met the criteria: · Must show working out · Use the correct units of measurement · And use formulas right through. Remember, answers are only part of the solution. You must show how you got there and be able to document and communicate your problem solving technique. Part 4. criteria has a subset of questions. Some higher criteria questions will draw on you to interpret, compare and draw conclusions of worked solutions. Format: Parts 1, 2, 4, 5, : Written calculations and graphical methods. Part 3 requires a written explanation in addition to equations. explanation which should include an equation to illustrate. Where references are used, follow Harvard Referencing System including in-text citations. Student declaration I certify that the work submitted for this assignment is my own and research sources are fully acknowledged. Student signature: Date: Unit Learning Outcomes LO1 Identify Solutions to problems within static mechanical systems. Assignment Brief and Guidance Scenario You are employed by the Air Accident branch of the Civil Aviation Authority ( CAA ) Your remit is to test both through calculation and laboratory experiments component parts of aircraft which have crashed to assisting in determining if it was due to pilot error or mechanical failure of components that form the airframe. If due to component failure colleagues will compere your data against the design data. This will further bring focus on if it was design or faulty manufactured components, or sub-standard materials used to manufacture the components. Due to your sphere of knowledge you are also asked to test through calculation proposed retrospective modifications to an existing design. Part 1. You are presented with a section of fuselage comprising of Aluminium alloy beams. The main beam shows signs of stress due to bending. Your team deduced that from the position of the section at the scene and the fuselage outer skin being intact it was not caused by the impact. Your remit it to determine the magnitude and distribution of the bending moments and stress for the beam. The design confirms for your calculations it can be considered as a “ Simply Supported Beam “ Your results will be used by colleagues to compare against the design requirements which included a FoS. The Beam section is 10 Metres in length. With a UDL of 2.5 kNm and its maximum design loading of 8kN is located centrally as a point load where it acts as a part support for the main wing spar. Your brief is to produce the calculations and diagrams to illustrate your findings when presented to the executive. Part 2. The aircraft wings require analysis. In particular the main spar. Because it is coupled to the beam you previously analysed, and as it is the only support for the wing’s main spar. The forces, bending moments, and shear stress the wing is subjected to is transferred to the beam you previously analysed. As it is supported only at one end namely the beam it is considered to be a cantilever beam. As in the previous task you are required to compile your results showing all formulas, equations, workings, and graphical modelling. The spar is 12 Metres long and has a mass of 100 kg per metre. The design specification states the Rolls Royce Trent Jet Engine has a mass of 6246 kg and is located mid point along the spar. Calculate the bending moment, shear stress and illustrate the distribution using graphical methods. Part 3. The submission of the results of test from Part 1. Caused a question to be raised. That being, Was the correct geometrical shape / Beam profile selected by the design team ? You are to write a report illustrating why I section beams are chosen to support loads. You should include equations which explain what, and how the first and second moments are and how they affect the magnitude of both the bending moments and stress. Part 4. You have been asked to form part of the team to investigate and validate a design change for the wheel axles on an aircrafts landing gear, which are 2 Metres long. The axles will be subjected to the effects of torsion which will be subject to the effects of torsion. The design data states the maximum sheer stress including FoS is given at 50 MPa and will be subjected to an equivalent power loading of 44.742 kilo Watts, and the wheels will have attained a maximum rotation of 5 revolutions per second. The Material used had a Modulus or rigidity of 70 GPa ( a ) determine what the minimum diameter of the shaft should be. ( b ) The resulting angle of twist. ( c ) What would be the sheer stress if it was replaced with a hollow tube with a wall thickness of 5mm instead of solid bar. ( d ) How would this affect the shear stress if the wall thickness was increased to 10mm ( e ) What would the new angle twist be. Part 5. From your calculations in part 4 determine what material the designer has based his calculations on. Resources Textbooks John Bird & Carl Ross, Mechanical Engineering Principles, Fourth Edition, Routledge. ISBN 978-0-367-25324-0 BOLTON, W. (2006) Engineering Science. 5th Ed. London: Routledge. TOOLEY, M. and DINGLE, L. (2012) Engineering Science: For Foundation Degree and Higher National. London: Routledge. Journals International Journal of Engineering Science. International Journal of Engineering Science and Innovative Technology. Websites https://www.khanacademy.org/ Khan Academy Physics (Tutorials) Learning Outcomes and Assessment Criteria Pass Merit Distinction LO1 Identify solutions to problems within static mechanical systems D1 Calculate the magnitude of shear force and bending moment in a cantilever / encastre’ beams for a variety of applications. P1 Calculate the distribution of shear force, bending moment and stress due to bending in simply supported beams. P2 Justify the selection of standard rolled steel sections for beams and columns. P3 Determine the distribution of shear stress and the angular deflection due to torsion in solid and hollow circular shafts. M1 Determine the material of a circular bar from the experimental data of angle of twist obtained from a torsion test.