Sensitivity Analysis of Holdback Bar Release Load during Catapult-Assisted Takeoff of Carrier-Based Aircraft

Abstract

The release load of holdback bar will affect the safety of catapult-assisted takeoff of carrier-based aircraft, and the accurate control of releasing the load will ensure success. The magnitude and the control accuracy of release load are important parameters which impact the takeoff performance, therefore unstable release load and insufficient release precision are the main factors affecting the takeoff safety. In this paper, mechanical models of the carrier-based aircraft in the catapult-assisted takeoff tensioning state and gliding state after release are established based on multi-body dynamics, contact mechanics and tribological theory, and the influence of the release load of the holdback bar on the catapult-assisted takeoff performance is analyzed. Furthermore, a kinetic model of the holdback bar device is established, and the kinetic characteristics of the release process of the holdback bar are studied. Based on the kinetic model and friction model of the holdback bar, the influencing factors of the sensitivity of the holdback bar release load are analyzed and the structural parameters are optimized. The results show that the released load decreases slowly with the increase of the contact surface angle of the holdback bar structure and increases rapidly when that angle reaches the critical value; besides, the release load increases slowly with the increase of the friction coefficient of the contact surface and increases faster when the critical friction coefficient is reached.

A Finite Element Model for a 6 × K31WS + FC Wire Rope and a Study on Its Mechanical Responses with or without Wire Breakage

“…Obviously, the maximum stress obtained by the analytical analysis is 297.33 Mpa bigger, the deviation is 19.85%. The reasons accounting for the deviation could be summarized as: (1) The assumption that the fiber core does not bear any load in the analytical model may lead to a bigger result; (2) The equivalent modulus E c may overestimate the stiffness of the assumed strand; (3) The strand of wire rope is not straight thus our assumption will certainly increase the stiffness of the strand.…”

“…A wire rope is a kind of component with a special spatial helix structure. It has good resistance to wear, fatigue, and shock, and is widely used in civil engineering, shipbuilding, aerospace engineering, and other industrial fields [1,2]. The core of a 6 × K31WS + FC wire rope is made of fiber, which has good performance in oil storage.…”