F-14 Tomcat Tail Hook Safety Analysis
DP 209
Degree Project
F-14 Tomcat Tail Hook Safety Analysis Under Impact Load Instructor: Submitted By: Wycliffe Falconer
Table of Contents
Abstract ……………………………………………………………... 4
Introduction ……………………………………………………………. 5
About the Material …………………………………………………… 6
Calculations ……………………...…………………………………. 7
Analysis on Catia …………………………………………………….. 11
Example of Failure …………………………………………………….. 13
Conclusion …………………………………………………………… 14
References …………………………………………………………….. 15
Abstract
The United States Navy 's aircraft carrier is capable …show more content…
The alloy steel is a material very resistant capable of withstanding forces of grate magnitude either tension or compression. Steel is not an element; it is an alloy of iron containing less than 1% carbon to make it stronger. The process of steelmaking had multiple changes in the last century to meet regulations based on the political, social and technological atmosphere, especially in the last decades since global warming became the most important factor. Steelmaking involves three steps which are melting, purifying and alloying. In the alloying process it is mixed with other elements such as manganese, nickel cobalt; depending on the desired alloy properties. The density of the alloy steel is 7850 kg/m^3, the elastic modulus is 190-210 GPa and the yield strength is 366-1793 MPa. These properties make the alloy steel the most suitable material for the Tomcat from an engineer’s perspective.
Calculations P = Impact Load = 225 Kip F.S. = Factor of Safety
D = Diameter of Tail Hook = 3.75 in Fs = Shear Force d = Diameter of Pin = 1.65 in.
Calculating the Stress applied at hook
Equation for stress σapplied = P/Ahook + (Mz*C/Iz) Area of the hook
Ahook = (π * D^2)/4
Ahook = (3.1416) *(3.75 * 3.75) /4
Ahook = 11.044
Moment about neutral axis
Mz = Force x Distance Mz = 225 * 2 = 450 …show more content…
The factor of safety of the hook obtained from the calculation was 2.6, which is slightly smaller than the factor of safety for the pin at 2.66. If failure occurs, it will happen on the bottom surface of the hook first rather than the bracket, which is the area under tension.
The factor of safety is very important because a very low factor of safety may lead to fatal accidents, jeopardizing not only the lives of the pilots but also the personnel working on the flight deck. The recovery, investigative process as well as time and monetary costs can be extensive and as such are to be avoided. This explains the reason for a high factor of safety which is to minimize the percentage of failure. The tail hook is designed for F – 14 Tomcats, but it can also be used for planes with similar weight such as the F -18 and F-22. This design also works for heavier airplanes, the only modification that needs to be made is increasing the diameter of the tail hook and the pin to carry more stress and shear.
References
Chatterjee, Amit. "Recent Developments in Ironmaking and Steelmaking." Iron and Steelmaking. 22:2 (1995), pp.
Degree Project
F-14 Tomcat Tail Hook Safety Analysis Under Impact Load Instructor: Submitted By: Wycliffe Falconer
Table of Contents
Abstract ……………………………………………………………... 4
Introduction ……………………………………………………………. 5
About the Material …………………………………………………… 6
Calculations ……………………...…………………………………. 7
Analysis on Catia …………………………………………………….. 11
Example of Failure …………………………………………………….. 13
Conclusion …………………………………………………………… 14
References …………………………………………………………….. 15
Abstract
The United States Navy 's aircraft carrier is capable …show more content…
The alloy steel is a material very resistant capable of withstanding forces of grate magnitude either tension or compression. Steel is not an element; it is an alloy of iron containing less than 1% carbon to make it stronger. The process of steelmaking had multiple changes in the last century to meet regulations based on the political, social and technological atmosphere, especially in the last decades since global warming became the most important factor. Steelmaking involves three steps which are melting, purifying and alloying. In the alloying process it is mixed with other elements such as manganese, nickel cobalt; depending on the desired alloy properties. The density of the alloy steel is 7850 kg/m^3, the elastic modulus is 190-210 GPa and the yield strength is 366-1793 MPa. These properties make the alloy steel the most suitable material for the Tomcat from an engineer’s perspective.
Calculations P = Impact Load = 225 Kip F.S. = Factor of Safety
D = Diameter of Tail Hook = 3.75 in Fs = Shear Force d = Diameter of Pin = 1.65 in.
Calculating the Stress applied at hook
Equation for stress σapplied = P/Ahook + (Mz*C/Iz) Area of the hook
Ahook = (π * D^2)/4
Ahook = (3.1416) *(3.75 * 3.75) /4
Ahook = 11.044
Moment about neutral axis
Mz = Force x Distance Mz = 225 * 2 = 450 …show more content…
The factor of safety of the hook obtained from the calculation was 2.6, which is slightly smaller than the factor of safety for the pin at 2.66. If failure occurs, it will happen on the bottom surface of the hook first rather than the bracket, which is the area under tension.
The factor of safety is very important because a very low factor of safety may lead to fatal accidents, jeopardizing not only the lives of the pilots but also the personnel working on the flight deck. The recovery, investigative process as well as time and monetary costs can be extensive and as such are to be avoided. This explains the reason for a high factor of safety which is to minimize the percentage of failure. The tail hook is designed for F – 14 Tomcats, but it can also be used for planes with similar weight such as the F -18 and F-22. This design also works for heavier airplanes, the only modification that needs to be made is increasing the diameter of the tail hook and the pin to carry more stress and shear.
References
Chatterjee, Amit. "Recent Developments in Ironmaking and Steelmaking." Iron and Steelmaking. 22:2 (1995), pp.