Torque Capacity and Crack Propagation Analysis of Fiber-reinforced Composite Hollow Transmission Shaft

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Addis Ababa University


The main purpose of this thesis is to investigate torque capacity and crack propagation resistance of glass fiber-reinforced polyester polymer composite material. This has been done in order to use this composite material for the transmission shaft of Hidasie helicopter (model of H260L helicopter) of Dejen Aviation Engineering Complex, DAEC. A glass fiber-reinforced polyester polymer composite hollow transmission shaft is manufactured in filament winding machine by winding of impregnated fiber around a mandrel layer by layer with different orientation angle and stacking sequence. The elastic engineering constants of composite transmission shaft are also determined using the Classic Laminate Theory, CLT. An experiment on the torsion testing machine reveals that the torque capacity of the hollow transmission shaft increases with increasing its thickness. It also shows that the [+450/-450/ 900]2s stacking sequence with six number of layers is capable to carry the torque which is applied to the transmission shaft of the helicopter. Analytical analysis on its torque capacity, crack propagation resistance, and torsional buckling capacity has been also made. Linear Elastic Fracture Mechanics, LEFM is used to analyze its crack propagation by taking a through-thickness central crack. The stress at the crack tip is analyzed hence the glass fiber-reinforced polyester polymer composite transmission shaft has good resistance to crack propagation. ANSYS finite element software is used to perform the numerical analysis for the transmission shaft. Full scale transmission shaft specimen is analyzed. The results show that the static torque capacity is significantly affected by changing orientation angle, stacking sequences and number of layers. A Good agreement is obtained among the finite element predictions and experimental and analytical results. And finally, few recommendations are also made for future study.



Crack Propagation, Transmission Shaft, Fiber-reinforced