Aircraft Impact Force
The containment of the nuclear power plant (NPP) is the outermost and last safety barrier of the nuclear reactor, the protective performance of which is rather critical to prevent the leakage of radioactive fission products.
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Aircraft Impact Force
8.1
Introduction
The containment of the nuclear power plant (NPP) is the outermost and last safety barrier of the nuclear reactor, the protective performance of which is rather critical to prevent the leakage of radioactive fission products. However, with the increasingly rampant terrorist attacks as well as the rapidly growing numbers of passenger planes in-service, the NPP containment is confronted with more deliberate and accidental impacting threats by commercial aircraft. However, before September 11, 2001, the existing NPP containments were not specifically designed to resist any external impact load greater than a light aircraft crash force, and only the probabilistic assessment method was used in the risk evaluation of large commercial aircraft impact accident. In particular, after the 9/11 terrorist attack, the commercial aircraft collision with the NPP containment has attracted much attention in the field of nuclear safety. In 2009, the USA Nuclear Regulatory Commission (NRC 2009) required that the newly built NPP containments must take into consideration of large commercial aircraft impact load (Jiang and Chorzepa 2014). The aircraft impact force should be firstly investigated in detail since the impact load directly affects the local failure and global response of the NPP containment. To determine the aircraft impact force, Riera (1968) developed a one-dimensional rigid perfectly plastic model to predict the normal impact force of aircraft hitting on a rigid flat target approximately, which was recognized as the Riera function and widely used thereafter. Dritter and Gruner (1976) put forward a differential method to calculate the impact force by considering the elasto-plastic material properties of aircraft. Afterward, Wolf et al. (1978) established a lumped mass-spring model, in which the lumped mass of aircraft is distributed in N nodes connected by elasto-plastic springs, and the predicted results fit well with the Riera function. In the actual impact process, the scattering debris will lead to the losses of energy and mass, which may weaken the impact force. Based on the energy © Science Press, Beijing and Springer Nature Singapore Pte Ltd. 2017 Q. Fang and H. Wu, Concrete Structures Under Projectile Impact, DOI 10.1007/978-981-10-3620-0_8
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conservation law, some modifications to the Riera function were performed. Hornyik (1977) introduced a coefficient to the Riera function based on the energy conservation law. However, the exact value of the coefficient was not obtained due to the lack of experimental data. Bahar and Rice (1978) gave a simplified derivation of the aircraft impact force-time history and derived the above coefficient to be 0.5. However, Riera (1980) found that the coefficient suggested by Bahar and Rice (1978) was a lower limit to the impact force-time history from a view of the energy balance. The accurate modification values were not obtained until that an F-4 fighter impact experiment on a flat concrete panel was conducted by Sugano
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