Impact induced dynamic response and failure behavior of aircraft structures

2022 ◽  
Vol 129 ◽  
pp. 100792
Author(s):  
Valentina Lopresto
2021 ◽  
Vol 12 (1) ◽  
pp. 20
Author(s):  
Ziwei Ge ◽  
Hongyan Liu

The landslide triggered by earthquakes can cause severe infrastructure losses or even fatalities. The high-steep rock slide is the most common type of landslide in the earthquake area. In an earthquake, the ground moves randomly in all directions, two horizontal directions (East-West (EW) direction, North-South (NS) direction) and one vertical direction (Up-Down (UD) direction). Even though extensive studies have been carried out on the earthquake-triggered landslide, the effects of each single seismic wave and the three-directional seismic waves are not considered. This study aims to evaluate the effects of different types of the seismic waves on the dynamic response and failure behavior of the high-steep rock slide. To investigate the effects of each single seismic wave and three-directional seismic wave, this study presents a numerical model with four types of seismic waves, e.g., East-West (EW) direction, North-South (NS) direction, Up-Down (UD) direction, and three-directional wave (EW_NS_UD). The numerical results revealed that the types of the seismic waves have significantly different effects on the dynamic process, failure behavior, run-out distance, velocity, and deposition of the high-steep rock slide.


Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1920
Author(s):  
Yan Peng ◽  
Yang Liu ◽  
Wei Zhang

The structural parts of construction machinery mostly fail due to impact load, but current research on the failure behavior of the impact load has not established a complete theoretical system. Based on wave theory and fracture mechanics, this paper analyzed the wave behavior of shock stress waves and established a model of shock stress wave propagation. Given the dynamic response behavior of the stress and strain field at the crack tip, dynamic fracture mechanics theory was used to solve the dynamic fracture strength stress factor and evaluate the dynamic fracture performance of the structure with crack damage under shock waves. Through dynamic response analysis and numerical calculation of the typical SHPB (split Hopkinson pressure bar) test standard compact tension (CT) specimens under the short-term strong shock stress wave, the stress and strain evolution law of the material under the shock wave was analyzed, and the correlation of the shock stress wave was verified. This research work can meet the requirements of engineering design and has practical engineering significance, playing an important role in material safety design.


2022 ◽  
Vol 2022 ◽  
pp. 1-16
Author(s):  
Yu Liang ◽  
Honggang Wu ◽  
Tianwen Lai ◽  
Hao Lei ◽  
Mingzhe Zhu ◽  
...  

In order to further understand the instability mechanism and geohazard causation when the main sliding path of the slope body is parallel to the path of the bridge, the corresponding bridge-landslide parallel system is constructed for shaking table tests. This paper summarizes the combination forms of bridge-landslide model under different position and focused on the slope body located above the bridge deck. Firstly, based on the shaking table test results of El Centro (1940), the failure behavior of bridge-landslide parallel system was evaluated, and the changes of acceleration and deformation of bridge pile were subsequently analyzed. Then, the interaction bridge structure and sliding body were explained by the spectral features. The main conclusions are as follows. First, in the model test, the landslide belongs to the thrust-type landslide. Due to the barrier function of the bridge, the main failure site of landslide occurs in the middle and trailing edge of slope body. At the same time, the acceleration value of earthquake waves is 0.3 g, which is the key to this variation. Second, the acceleration response of the measuring points on the bridge pile and landslide increases with the increase of ground elevation. If the slope structure is damaged severely, the deformation response of weak interlayer is inconsistent with the surrounding soil structure. Third, with the increase of excitation power, the dominant frequency of bridge-landslide parallel system gradually transitions from low to high frequency rate, and the interaction of the parallel system weakens the influence of river direction on frequency. Finally, under the same working condition, the dynamic response of the measuring points has obvious regularity with the change of situation. But the response of the same points is not regular due to the different earthquake excitation intensity.


2011 ◽  
Vol 410 ◽  
pp. 321-324
Author(s):  
B. Han ◽  
Feng Xian Xin ◽  
Feng Jin ◽  
T.J. Lu

Hail impact has been a long lasting threat for aircraft structures such as leading edges and forward sections. To mimic the physical process of hail impact on aircraft structures, a FEM model is established for all-metal sandwich structures having four different kinds of cores: corrugated core, pyramidal lattice core, metal foam core, and corrugation-foam hybrid core. Smoothed particle hydrodynamic (SPH) method is employed to predict the failure behavior of the hail, whilst the sandwich structures are described by a Lagrangian reference configuration. It is demonstrated that the sandwich structures with hybrid core outperforms the other three types for withstanding hail penetration as well as absorbing impact energy.


2021 ◽  
Author(s):  
Fan Feng ◽  
Shaojie Chen ◽  
Xingdong Zhao ◽  
Diyuan Li ◽  
Xianlai Wang ◽  
...  

Abstract The occurrence of disasters in deep mining engineering has been confirmed to be closely related to the external dynamic disturbances and geological discontinuities. Thus, a combined finite-element approach was employed to simulate the failure process of an underground cavern, which provided insights into the failure mechanism of deep hard rock affected by factors such as the dynamic stress-wave amplitudes, disturbance direction, and dip angles of the structural plane. The crack-propagation process, stress-field distribution, displacement, velocity of failed rock, and failure zone around the circular cavern were analyzed to identify the dynamic response and failure properties of the underground structures. The simulation results indicated that the dynamic disturbance direction had less influence on the dynamic response for the constant in situ stress state, while the failure intensity and damage range around the cavern always exhibited a monotonically increasing trend with an increase in the dynamic load (stress-wave amplitudes). The crack distribution around the circular cavern exhibited an asymmetric pattern, possibly owing to the stress-wave reflection behavior and attenuation effect along the propagation route. Geological discontinuities significantly affected the stability of nearby caverns subjected to dynamic disturbances, during which the failure intensity exhibited the pattern of an initial increase followed by a decrease with an increase in the dip angle of the structural plane. Additionally, the dynamic disturbance direction led to variations in the crack distribution for specific structural planes and stress states. These results indicate that the failure behavior should be the integrated response of the excavation unloading effect, geological conditions, and external dynamic disturbances.


Author(s):  
Edward Seckel ◽  
Ian A. M. Hall ◽  
Duane T. McRuer ◽  
David H. Weir
Keyword(s):  

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