In-Plane Dynamic Response Analysis of Hexagonal and Reentrant Honeycombs Under Uniaxial Impact Loading

Author(s):  
Zhen Li ◽  
Qiang Gao ◽  
Liangmo Wang ◽  
Jun Tang

To investigate their in-plane dynamic response, a rigid plate with mass was given an initial velocity to impact (square) honeycombs in the X1 and X2 directions, respectively. Firstly, the impact model was built and validated. Then, impact resistance capacity research was conducted. Results showed that each honeycomb performed similarly in X1 and X2 directions, and the reentrant honeycomb usually used smaller displacement and time to absorb the same amount of kinetic energy. Thus, it is better for application if these factors were the main concerns. After that, the nominal stress at the proximal and distal ends were discussed under various impact velocities. It is shown that, under impact loading, the reentrant honeycomb generally showed higher initial peak stress as well as lower plateau stress at both proximal and distal ends. In addition, combining these with the deformation process of honeycombs, it was concluded that the formation of the plateau area of the nominal stress curve is related to the crushing displacement of the impact plate as well as the collapse of cells.

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yue Wang ◽  
Jun Liu ◽  
Zhimin Xiao ◽  
Futian Zhao ◽  
Yi Cheng

Reinforced concrete (RC) slab is an important component in civil construction and protection engineering, and its dynamic response under impact loading is a complex mechanical problem, especially for two or multiple continuous impact loads. In this paper, a series of drop hammer impact tests were carried out to investigate the dynamic response of RC slabs with two successive impacts. The time history of impact force and the failure characteristic of the slab surface were recorded. Moreover, four influence factors, including slab thickness, reinforcement ratio, impact location, and drop hammer height have been discussed. Besides, a 3D numerical model based on the finite element method (FEM) was established to expand the research of constrained force, deflection, and vertical stress of an RC slab. The results show that increasing the slab thickness and reinforcement ratio can improve the impact resistance of an RC slab. The impact point location and drop hammer height have a great influence on the dynamic response of the RC slab. In addition, the RC slab will have more obvious damage under the second impact, but the dynamic response becomes weaker. It may be because of the local damage in the concrete caused by the first impact that would weaken the propagation of vibration.


Author(s):  
Makoto Tanabe ◽  
Hajime Wakui ◽  
Nobuyuki Matsumoto

Abstract A finite element formulation to solve the dynamic behavior of high-speed Shinkansen cars, rail, and bridge is given. A mechanical model to express the interaction between wheel and rail is described, in which the impact of the rail on the flange of wheel is also considered. The bridge is modeled by using various finite elements such as shell, beam, solid, spring, and mass. The equations of motions of bridge and Shinkansen cars are solved under the constitutive and constraint equations to express the interaction between rail and wheel. Numerical method based on a modal transformation to get the dynamic response effectively is discussed. A finite element program for the dynamic response analysis of Shinkansen cars, rail, and bridge at the high-speed running has been developed. Numerical examples are also demonstrated.


2019 ◽  
Vol 19 (08) ◽  
pp. 1950091 ◽  
Author(s):  
Wuchao Zhao ◽  
Jiang Qian

Reinforced concrete (RC) beams under the impact loading are typically prone to suffer shear failure in the local response phase. In order to enhance the understanding of the mechanical behavior of the RC beams, their dynamic response and shear demand are numerically investigated in this paper. A 3D finite-element model is developed and validated against the experimental data available in the literature. Taking advantage of the above calibrated numerical model, an intensive parametric study is performed to identify the effect of different factors including the impact velocity, impact mass and beam span-to-depth ratio on the impact response of the RC beams. It is found that, due to the inertial effect, a linear relationship exists between the maximum reverse support force and the peak impact force, while negative bending moments also appear in the shear span. In addition, the local response of the RC beams can be divided into a first impact stage and a separation stage. A shear plug is likely to be formed near the impact point at the first impact stage and a shear failure may be triggered near the support by large support forces. Based on the simulation results, simplified methods are proposed for predicting the shear demand for the two failure modes, whereas physical models are also established to illustrate the resistance mechanism of the RC beams at the peak impact force. By comparing with the results of the parametric study, it is concluded that the shear demand of the RC beams under the impact loading can be predicted by the proposed empirical formulas with reasonable accuracy.


Author(s):  
Xiaoyao Shen ◽  
Yongcheng Xie

The control rod drive mechanism (CRDM) is an important safety-related component in the nuclear power plant (NPP). When CRDM steps upward or downward, the pressure-containing housing of CRDM is shocked axially by an impact force from the engagement of the magnetic pole and the armature. To ensure the structural integrity of the primary coolant loop and the functionality of CRDM, dynamic response of CRDM under the impact force should be studied. In this manuscript, the commercial finite element software ANSYS is chosen to analyze the nonlinear impact problem. A nonlinear model is setup in ANSYS, including main CRDM parts such as the control rod, poles and armatures, as well as nonlinear gaps. The transient analysis method is adopted to calculate CRDM dynamic response when it steps upward. The impact loads and displacements at typical CRDM locations are successfully obtained, which are essential for design and stress analysis of CRDM.


2007 ◽  
Vol 336-338 ◽  
pp. 2592-2594
Author(s):  
Wen Yan Wang ◽  
Jing Pei Xie ◽  
A.H. Wang ◽  
Wei Li ◽  
Zhong Xia Liu

A multiple impact loading experiment was designed to investigate the cracking behavior in the transitional regions of laser-clad iron base alloy on an electrolytic low titanium aluminium alloys under multiple impact loading in this study. The concept of TCR (transitional crack ratio) was introduced to evaluate the crack resistance of the transitional regions to multiple impact loading (impact resistance). Results showed that the substrate temperature during laser cladding process and the scanning velocity have significant influences on the microstructure of the transitional regions and then the impact resistances of the laser-clad iron alloy coating. The laser-clad iron base alloy coatings obtained at the substrate temperature within 275 ~ 320°C displayed the best impact resistance. Furthermore, the crack mechanism in the transitional regions was analyzed.


Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Bailong Li ◽  
Changming Wang ◽  
Yanying Li ◽  
Yiao Liu ◽  
Nan Jiang ◽  
...  

Based on the coupled SPH-DEM-FEM numerical method, this paper analyzes the dynamic interaction of solid debris flow particle-liquid debris flow slurry-retaining dam in order to explore the dynamic response of retaining dam under the impact of the solid-liquid two-phase debris flow and delves into the process of the debris flow impact on the dam, the impact force of debris flow, and the elastic-plastic time-history characteristics of the dam under different slopes of trapezoidal grooves. The calculation results show that the coupled SPH-DEM-FEM method can vividly simulate the impact behavior of the solid-liquid two-phase debris flow on the dam, reproduce the impact, climbing, and siltation in the process of the debris flow impact; the dynamic time-history curve of the retaining dam is consistent with the law of the literature, and the result of the debris flow impact force obtained is close to that of the empirical formula. Moreover, this paper studies the impact force distribution of the debris flow impact process. The results have a certain reference value for the study of the dynamic response of the retaining dam under the impact of the solid-liquid two-phase debris flow and the engineering design of the debris flow-retaining dam.


2012 ◽  
Vol 170-173 ◽  
pp. 1361-1366 ◽  
Author(s):  
Zhao Bo Meng ◽  
Teng Fei Zhao ◽  
Shi Cai Cui ◽  
Jie Jin

Taking Xi’an Bell Tower and metro line 2 as research background, at first, according to the theory of Euler-Bernoulli beam in Winkler foundation, the analysis model of train-track-foundation system was established, and then, time-history curve of metro-induced loading acts on tunnel structure is obtained by using Matlab produce platform. Secondly, two-dimensional finite element model of the structure-soil-tunnel interaction model was established using ANSYS. Taken loading time delay into consideration for the first time, dynamic response law of the bell tower under the metro-vibration loading is obtained. Finally, the impact of metro line 2 on Xi’an Bell Tower was evaluated according to the Technical specification for protection of historic buildings against man-made vibration.


2014 ◽  
Vol 1051 ◽  
pp. 857-861
Author(s):  
Bin Tian ◽  
Da Wei Liu ◽  
Long Long Zhu

In order to study the impact resistance capability of dump truck bodies floor, a simulation model of dump truck bodies floor and impact hammerheads made of metal materials were designed, and a strain test system of bodies floor under impact loading was established, a measurement of the stress of bodies floor model was made to obtain the law of stress variation about key point of truck bodies floor model. The research laid the foundation for the analysis of impact resistance capability of dump truck bodies floor using finite element method as well as provided a reference for the structural optimization of truck bodies floor.


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