Reference no: EM133867190

AIRCRAFT DESIGN

Question 1

Name the different signal conditioning techniques applied on sensor data. Why different sensor conditioning methods should be applied on measured data?

Briefly explain why the following steps are necessary for measurement,
Briefly explain the methods that can be used for thermal compensation in strain gauge measurements.
Briefly explain, why the strain gauge needs a three-wire connection instead of two wires.

What is the key difference between a ‘Voltage' mode piezoelectric accelerometer and a ‘Charge' mode piezoelectric accelerometer? In what case(s) is the ‘Charge' mode a better option and why?

An instrument has an accuracy of ± 10 % FS (Full Scale) and measures resistance from 0 to 1500 Ω. What is the resistance range in an indicated measurement of 397 Ω. Find the accuracy in the measured value of resistance R.

Question 2:

Briefly explain in your own words the working principles of at least three different methods to measure vibration. Discuss their main advantages and disadvantages and typical applications.

Briefly describe the working principle of (i) Sonar and (ii) Lidar.

(c) Briefly explain the working principle of three types of sensors: (i) Eddy current probe (ii) Hall Effect senor (iii) Capacitive sensor.

d) Consider the signal conditional circuit with RTD temperature sensor represented by resistance Rs as shown in Figure (2). The equation for RTD temperature sensor is given as,

Where k = 0.025 °c^-1, T₀ = 00C, R(T₀) = R₀ = 75 kΩ , R₁ = 2R₀ , V_in = 9V

Assume that the output voltage (Vout) has a range of ± 15 V. Calculate the corresponding measurement range of the input temperature.
Hint: This could be achieved by finding the relationship between Temperature and Output voltage.

Question 3:

Briefly describe the working principles of capacitive probe, reed switch sensor and Magnetoresistance sensor. In which application does a capacitive proximity probe work better than other types of proximity probes (i.e. eddy current and magnetic) and why?

Briefly describe the working principle of ultrasonic sensors. Why does some sensors have three- wire electrical connection instead of two wires (Explain this for hall effect sensors)?

Consider an unbalanced Wheatstone Bridge as shown in Figure. Calculate the value of unknown Resistance value R1. What is the value of resistor R3 required to balance the bridge circuit?

Critically evaluate different sensor types and identify two sensor types that can be used for detecting structural damage in offshore oil rig components. The sensors must operate effectively under the following conditions: Harsh environment, including extreme temperatures (-40°C to +50°C), high wind and wave loads, fluctuating mechanical stresses, continuous exposure to vibrations, and external factors such as saltwater corrosion, rain, ice accumulation, and lightning strikes, while maintaining long-term durability, accuracy, and energy efficiency. Clear justification should be provided for the choice of sensors, their mounting methods, and how they relate to detecting specific types of structural damage.

Question 4:

Design and develop a sensing suite for condition monitoring and fault detection of high-speed rocket engine turbopump bearings. The design should emphasize optimal sensor selection, integration, and placement to achieve precise, reliable, and early fault detection. The sensing system must function effectively under extreme operational conditions, including extreme temperatures ranging from cryogenic (-250°C) to over 200°C, extremely high rotational speeds (> 35,000 rpm), intense vibrations (>100 g), highly variable load profiles throughout different mission phases, exposure to aggressive cryogenic or hypergolic propellants and lubricants, while ensuring long-term durability, accuracy, and energy efficiency. A multi-sensor approach should be employed to determine the most suitable sensors for detecting bearing defects, misalignment, wear, and abnormal operating behaviours, optimizing both performance and resilience in extreme aerospace environments.

Critically evaluate and identify the most critical parameters that need to be measured for effective condition monitoring and fault detection of high-speed rocket engine turbopump bearings. Justify the selection of each parameter with a short description.

Critically evaluate and identify the sensor type and sensor technology to measure the critical parameters selected in part (a). The sensor must operate in extreme conditions as given above (high temperatures, vibrations, rotational speeds, exposure to contaminants) and ensure long-term reliability, durability, and accuracy while minimizing energy consumption and maintenance requirements. Provide a short description justifying the selection of each sensor type and technology.

Determine sensor placement at critical bearing locations (e.g., inner race, outer race, rolling elements, bearing housing, lubrication path, etc.). Propose an optimal sensor mounting and sensor placement strategy for the selected sensors to ensure early fault detection while minimizing installation complexity and sensor wear. For sensor placement and mounting, consider the environmental and operational conditions given above.