Load Measurement Using a Strain Gauge - Lab Report Example

Design ReportDesign Report Template Load measurement using a strain gauge Instrumentation and Measurement ENM2104 Engineering Design Process TABLE OF CONTENTS 1.Introduction 3 1.1. Description of the Project 3 2.Implementation 3 2.1. Abstracting the Problem 3 2.2. Division of Tasks 3 2.3. Problems Faced 4 3.Sensor Selection 5 3.1. Identification of the Sensor Type 5 3.2. Performance Test of the Sensor 5 4.Measurement System Implementation 6 4.1. Hardware Configuration 6 4.2. Software Configuration 7 5.Conclusion 8 6.References 8 7.Appendices 9 1. Introduction 1.1. Description of the Project This project is focused on measuring the load on structural members. Thus, the purpose of the project is to measure the load of aircraft structural members using a strain gauge. An effective method for strain gauge calibration and installation in structures of aircrafts has been developed (Huff, 2013). This method ensures that lift or shear and torque of the flight can be determined effectively. A numerical method that involves combination of various bridges output is used to determine the loads. Such a method demands that pressure installations to be complete so that accuracy on the data of the load to be attained. 2. Implementation 2.1. Abstracting the Problem The main focus of the project is to measure the load of the structural members of aircrafts. Such measurements are essential for various activities, which include the development of the flight testing procedures, integrity of the structural demonstrations and the investigations of the research process. Strain gauge offers and effective strategy and means of measuring the load of the structural members of aircrafts. 2.2. Division of Tasks The tasks involve first calibration of the strain gauge to ensure that it has the potential and ability to take accurate readings as expected. The second task is the preparation of the surface where the strain gauge is to be attached. Such a preparation procedure involves surface cleaning and smoothening with sand paper. Solvent traces should also be removed to ensure that the surfaces at stuck together effectively (Buyuk et al., 2009). Failure to adhere to the cleaning requirement results in unpredictable measurements and poor binding of the gauge on the surface. Consequently, errors emerge from the measurements that are taken. The third task is the binding of the strain gauge on the surface of aircraft structural member while using cyanoacrylic glue. The final task is connecting the entire network of hardware to ensure that the measurements from the strain gauge are received on a digital display. Binding of the strain gauge on the surface of the structural member 2.3. Problems Faced The process of implementation of strain gauge fixing and measuring has several challenges and problems. For example, when binding the strain gauge of the surface of the structural members, it was complex to determine if the surface was truly clean for sticking the strain gauge. Moreover, the connection of the strain gauge to the structural members and digital display involved several wires of different lengths and purposes, which was somehow confusing. 3. Sensor Selection 3.1. Identification of the Sensor Type The sensor type is the strain gauge that has a variable resistance based on the force, which is applied on it. As such, strain gauge converts the force, weight, tension and pressure applied on it into an electrical resistance, which can be effectively measured using any means (Littell et al., 2008). The sensor is effective since it facilitates in detection of even the small elongations and deformations of the structural members. Further, the sensor aids in determination of the loads of the structural members in different areas. Nevertheless, the sensor may have inherent errors, which emerge from poor biding of the sensor on the surface of the structural member whose load is to be determined. 3.2. Performance Test of the Sensor Strain is regarded as the deformation or displacement, which occurs when external forces are applied on a stationery object. Such could be either compressive or tensile strain depending on the mode of the application of the external force. The gauge is also able to monitor contraction and expansion of a material. Thus, strain gauge performance is based on the strain values, which are measured on the surface of the structural part of the material. These values aid in stating the material stress, as well as predicting the endurance and safety level of the material. The gauge performance is the best and facilitates in gathering valid and accurate data on the load of the structural members of an aircraft. Performance of the strain gauge 4. Measurement System Implementation 4.1. Hardware Configuration The measurement procedures involve an electrical circuit, which comprises of strain gauges, which have a typical configuration of 4 arms (Wheatstone bridge). Such act as a subtraction and addition to the electrical network. The Wheatstone bridge creates room for temperature effects compensation and signal cancellation, which emerge from extraneous loading (Takeda et al., 2008). The normal output is a signal voltage of low level, which via signal amplifiers and condition becomes a higher level current or voltage. The signals act as parts of the system monitoring, analogue or digital display and form a control system of closed loop feedback. The initial low level signal may also be changed to a digital output. Schematic of the Wheatstone bridge Wheatstone bridge, which is complete, is excited using a stabilized DC supply and added conditioning electronics, which are zeroed at the point of measurement. As such, application of stress occurs at the bonded strain gauge, which results in changes of the unbalances and place of the Wheatstone bridge. Such produces a signal output. 4.2. Software Configuration Demonstration of the circuit sensor measurement process The orientation of the strain gauge is essential. For the aircraft structures, the gauges need to be attached on the surface during the measurement of strain. Such an attachment involves the use of special to ensure that the gauge is secured on the substrate effectively (Vulliez, 2013). Cyanoacrylic glue is essential for aircraft measurements since the gauge remain on the surface for a short time measurement. 5. Conclusion The use of strain gauge in load measurement aids in attainment of effectiveness in the process of measuring and transmitting data, which is essential in the validation of the structures for complete aircraft design and manufacture while ensuring safe operation and integrity. Strain gauge also has high fatigue life, redundancy, better working conditions and offers room for testing flexibility and improving the versatility of the system. As such, strain gauge is the most effective equipment for load measurement in aircraft structures. Such demands effective calibration and conditioning of the signals at surfaces where strain is to be measured. 6. References Buyuk, M., Kan, S., & Loikkanen, M. J. (2009). Explicit Finite-Element Analysis of 2024-T3/T351 Aluminum Material under Impact Loading for Airplane Engine Containment and Fragment Shielding. Journal of Aerospace Engineering, 22(3), 287-295. Huff, D. L. (2013). NASA Glenn's Contributions to Aircraft Engine Noise Research. Journal of Aerospace Engineering, 26(2), 218-250. Littell, J. D., Ruggeri, C. R., Goldberg, R. K., Roberts, G. D., Arnold, W. A., & Binienda, W. K. (2008). Measurement of Epoxy Resin Tension, Compression, and Shear Stress–Strain Curves over a Wide Range of Strain Rates Using Small Test Specimens. Journal of Aerospace Engineering, 21(3), 162-173. Takeda, S., Mizutani, T., Nishi, T., Uota, N., Hirano, Y., Iwahori, Y., & ... Takeda, N. (2008). Monitoring of a CFRP-Stiffened Panel Manufactured by VaRTM Using Fiber-Optic Sensors. Advanced Composite Materials, 17(2), 125-137. Vulliez, P. (2013). Distributed fiber-optic sensing solves real-world problems. Laser Focus World, 49(2), 60-67. 7. Appendices Appendix 1 Bonded strain gauge Read More