graduation thesis presentation by 福山（191162173）

Nanjing University of Aeronautics and Astronautics

UG. Thesis presentation 2015Department of Mechanical Engineering

School of Mechanical and Electrical Engineering– CMEE

Research On The Thickness Measurement of Hollow Structural Parts With

Complex Surfaces

An undergraduate thesis by

Faizan Naeem (191162173)Bachelors in Mechanical Engineering

Guided by Prof. Yucan fu

Zhengcai (PhD) 05/06/2015

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Index

Following is the list of the outline of thesis presentation.

• General introduction to the research topic • Turbofan and Hollow Fan Blade• Importance of Thickness measurement • Ultrasonic Thickness Measurement • Thickness Measurement Experiment • Thickness Measurement Signal Analysis • Conclusion

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• Prime work of my project was to Measure the thickness of hollow structure such as titanium hollow fan blade by NDT technique of ultrasonic testing. • An experimental setup was conducted

including fixture and test specimens for adjusting the blade to carry out experiments. By using gauge different results were evaluated by subjecting ultrasonic probe on several portion of blade.

• Thickness distribution were conducted and results were presented graphically.

• Obtained thickness distribution results were analyzed by using device signals, since it use sound waves to find thickness.

General Introduction

Hollow titanium fan blade for Trent engine

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• TurbofanIn order to generate an aircraft, thrust is

needed through an propulsion system , there for turbofan is used because of their high thrust and fuel efficiency.

Turbofan is highly fuel efficient because of its high thrust generation using equal amount of fuel used by the core turbine. (as Shown in second fig.)

• Hollow Fan BladeAs one of the core components of the

turbofan engine, the geometry and manufacturing precision of fan blade has a huge impact of bypass ratio on engine thrust to weight ratio and is an important factor in various aspects.

Turbofan and Hollow Fan Blade

Schematic Diagram of Blade

High bypass Turbo Fan engine

Turbine Fan Turbine

Front fanCompressor

Combustor

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• Structure of blade The structure of titanium wide-chord fan blade is ridged and primarily comprises of core veneer and wallboard. These core veneers are utilized as a part of the empty part which makes up two-third of the entire length of the blade staying some separation to the top, the base, the main edge and trailing edge. A blade incorporates an empty metal airfoil having an opening to an inside cavity in a first real surface. A metal spread is adhesively clung to an attachment conformed to the opening.

• Manufacturing Manufacturing of blades are extensively starts by molding and then hot forming process which includes SPF/DB technique

to form the blade into hollow structure. During the process blades are subjected to high temp and then instantly cooled. Later, after testing, NC machining is done for final form of blade.

Turbofan and Hollow Fan Blade

Leading edge bond

Core sheet

Hollow region bond

Stress concentration region Face sheet

Trailing edge bond

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• Significance

After the hot forming process and mounting blade, its wall thickness is inspected to check whether the tolerance of blade is in range or undesired. This is done by ultrasonic probe testing either manually or using various techniques. In my work Ultrasonic thickness gauge is being used by mounting blade on a fixture. By this measurement distribution of blade was carried out.

• Ultrasonic Thickness Measurement

Ultrasonic thickness method is taken under consideration, since UTM is a NDT which can measure the blade thickness without any harm. In order to perform thickness measurement, Ultrasonic thickness gages

can be utilized, a particular gauge uses ultrasonic probe to send sound waves traveling from one surface and then reflective back giving the smallest possible value. Such technique is immensely useful for measuring because of no harming to workpiece.

Importance of Thickness Measurement

Cross-section view of typical hollow fan blade

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• Experimental Setup

To carry out the experiment brief experimental set up was arrange including measuring device, fixtures, specimens and technical requirements subjected to experiments.

All four figures shows the complete experimental setup for experiment(from left to right), Vernier caliper & UT 3DL PLUS, work piece & specimen, Blade mounted on fixture with device, couplant and UT probe.

Thickness Measurement Experiment

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• Measuring process

Gauge tested with similar workpiece before measuring actual specimen.

Coordinate marked on both sides of blades to carry out thickness distribution.

Subject the ultrasonic probe using couplant to remove any gap, to measure the thickness distribution on all coordinates with three different values.

Obtained results were drew as a graph to and then signal analysis of the thickness distribution were carried.


Horizontal view of blade with marked coordinated

Ultrasonic 3DL Plus probe

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• Thickness Measurement Distribution results


No Coordinat

e PositionSide A Side B

1 2 3 Average 1 2 3 Average

1 -20 2.007 2.011 2.011 2.009667 1.939 1.946 1.938 1.941

2 -10 2.026 2.018 2.026 2.023333 2.016 2.016 2.023 2.018333

3 0 2.583 2.648 2.63 2.620333 2.317 2.301 2.299 2.305667

4 10 1.413 1.416 1.417 1.415333 1.801 1.816 1.81 1.809

5 20 1.613 1.612 1.618 1.614333 1.795 1.791 1.792 1.792667

6 30 2.177 2.176 2.177 2.176667 1.38 1.374 1.383 1.379

7 40 2.045 2.043 2.049 2.045667 1.537 1.539 1.543 1.539667

8 50 1.556 1.533 1.553 1.547333 1.557 1.553 1.55 1.553333

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9 60 1.55 1.55 1.551 1.550333 1.55 1.553 1.551 1.551333

10 70 1.559 1.553 1.556 1.556 1.556 1.549 1.55 1.551667

11 80 1.598 1.601 1.601 1.6 1.456 1.451 1.453 1.453333

12 90 1.979 1.976 1.981 1.978667 1.334 1.331 1.339 1.334667

13 100 1.963 1.957 1.961 1.960333 1.386 1.378 1.367 1.377

14 110 1.752 1.745 1.742 1.746333 1.516 1.513 1.526 1.518333

15 120 3.444 3.43 3.447 3.440333 3.454 3.451 3.447 3.450667

16 130 2.266 2.239 2.234 2.246333 2.01 2.014 2.014 2.012667

17 140 1.923 1.925 1.929 1.925667 1.851 1.848 1.846 1.848333


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• Graphical Representation For the graphical representation, an proprietary computer program Origin was used which is skilled at interacting scientific graphing and data analysis. The obtained values from the both sides (A and B) of blade were generated in the Origin. Along with the coordinates similar to blade. After putting select all the values and click right to use the plot option with further line + symbol to draw a graph. By using line + symbol command a graphical representation of blade thickness measurement distribution will appear.

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• Distribution Explanation

The graph shows the thickness distribution on blades of both sides that was taken by using ultrasonic method, though achieving thickness measurements, some of the measured values show small thickness range while some of shows large values accounted by process, this is because of the blade forming technique. During the process of hollow fan blade the consistency of metal flow during forming could have subjected to high temperature and its cooling process, which can lead its thickness uneven. Even in DB/SPF processes of blades 100% accuracy is impossible to achieve, however the rate of uneven thickness can be minimal.

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Thickness Measurement Signal Analysis

• Signal Analysis In order to analyze the signal analysis, official software for device called GaugeView was used; this software is specially made to run the signals to output devices. First after opening, software must be detective with the device via USB cable provided with gauge, after succession, open a file menu to get another catalogue that contains software data, once it appears more option will show up in the toolbar, from them select settings and use tool pictogram to let the software detects the device for digital running. Two positions on blade were measured and there signals

were transmit to the pc, to display the waveform of measured signals. Following is the figures of signal I and II from different positions of blades.

Signal transformation from device to PC.

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• Measurement signal (I) analysis for blade thickness, taken at specific position.

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• Measurement signal (II) analysis for blade thickness, taken at specific position.

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• Measurement signal (II) analysis for blade thickness, taken at specific position.

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It has been concluded that the ultrasonic thickness measurement method is highly successful in testing of hollow blade’s internal structure because of Non-destructive technology that allows us to measure it without any harm.

1. By using NDT an ultrasonic thickness measurement distribution was conducted on blade to obtain the hollow structural part thickness of blade. The experiment was successfully conducted and thickness results were obtained ultrasonically, the blade actual thickness was measured 2 mm from the both ends. With ultrasonic testing the range of blade thickness distribution was 1.377 ~ 3.44 inch.

2. With the ultrasonic gauge device, blade results were briefly analyzed through signal analysis, which successfully implements the signal and it thickness distribution results.

Conclusion

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Vita.

An undergraduate thesis by Faizan Naeem, this presentation was a part of under graduation program, that was conducted under the

supervision of my thesis academic and technical supervisor. Thesis and presentation for this project has solemnly composed and

written by me. The thesis has submitted under the partial fulfillment of the requirement of Bachelors in Mechanical Engineering.

Thank you.

graduation thesis presentation by 福山（191162173）

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