scholarly journals Method to evaluate the effect of inclination angle of steel open-type check dam on debris flow impact load

2018 ◽  
Vol 10 (1) ◽  
pp. 95-115 ◽  
Author(s):  
Toshiyuki Horiguchi ◽  
Yoshiharu Komatsu
Keyword(s):  
Debris Flow ◽  
Natural Disasters ◽  
Inclination Angle ◽  
Impact Load ◽  
Time History ◽  
Check Dam ◽  
Open Type ◽  
Inclination Angles ◽  
The Impact ◽  
Type Check

Although the latest statistics indicate a decrease in the number of victims of natural disasters in Japan, the number of sediment disasters has increased. A countermeasure against natural disasters is provided by the installation of a steel open-type check dam (hereafter, open Sabo dam). The open Sabo dam is expected to capture boulders (more than 1.0 m in diameter) contained in debris flow of which boulders concentrate in front part. When a debris flow impacts an open Sabo dam, the large impact load on the steel pipes are caused by the impact of boulders under debris flow. Therefore, it is important to evaluate the impact of both boulders and the following soil and small gravels including fluid force of the open Sabo dam from the design point of view. Although an open Sabo dam has various shapes especially, the every open Sabo dams is evaluated by the same design method in Japan. It is necessary to propose the load evaluation method in the experiment scale in contrast with different shape of open Sabo dam. This article presents an experimental approach to determine the effect of the front inclination angle of steel open Sabo dams on the impact load. The debris flow impacts 1/40 scale models of steel open Sabo dams which are set in a flow channel flume, and the debris flow load is measured by using three load cells placed horizontally at the back of the Sabo dam model. Different front inclination angles are set for each Sabo dam models. The time history of the impact load is examined by comparing the loads corresponding to four kinds of dams, which are different from the front inclination angles, and decrease of impact load considering the buffering effect of driftwoods in debris flow.

Study on the Impact Properties of a New Debris Flow Dam Based on Steel-Concrete Composite Structure

2014 ◽  
Vol 638-640 ◽  
pp. 2056-2059 ◽  
Author(s):  
Ya Xiong Liang ◽  
Xiu Li Wang ◽  
Chang Wu ◽  
Zhi Gang Lv
Keyword(s):  
Finite Element ◽  
Debris Flow ◽  
Impact Force ◽  
Impact Load ◽  
Weak Link ◽  
Time History ◽  
Type Model ◽  
Finite Element Software ◽  
New Type ◽  
The Impact

The impact force is one of the most weak link of the dynamics studies of debris flow for many years. To make the structure or components are better able to suffer the impact load such as debris flow, explosions, a new debris flow dam is designed by introducing this new type model with spring. It is simulated under boulder impact by using finite element software LS-DYNA.The stress distribution, impact and displacement time history curve under typical conditions are obtained. The results show that the resist impact effect of new debris flow dam is very obvious.

scholarly journals Analysis of Debris Flow Reduction Effect of Check Dam Types considering the Mountain Stream Shape: A Case Study of 2016 Debris Flow Hazard in Ulleung-do Island, South Korea

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Man-Il Kim ◽  
Namgyun Kim
Keyword(s):  
South Korea ◽  
Debris Flow ◽  
Observation Point ◽  
Mountain Stream ◽  
Check Dam ◽  
Open Type ◽  
Flow Reduction ◽  
Check Dams ◽  
Closed Type ◽  
Type Check

Ulleung-do is a volcanic island located 130 km east of the Gangwon-do province of South Korea. It is characterized by steep slopes covered with effusive rocks released from multiple volcanic activities. Having accumulated deep colluvium, Ulleung-do Island manifests a high vulnerability to landslides frequently caused by heavy rains or typhoons, debris flow, rockfall, and other disaster hazards in mountainous areas. Therefore, facilities and residential areas located in the lower areas of the island sustain widespread damage. Hence, the installation of check dams designed to reflect the area’s local conditions is required to avoid further damage. In line with that, this study analyzes the disaster cases in Ulleung-do’s mountain areas and the effect of check dams in debris flow reduction for each type using the KANAKO-2D model. At observation point 1, the result shows that the maximum rate of debris flow is reduced by 48.5% with an open-type check dam installed and 62.9% with a closed-type check dam installed from the level without a check dam. For observation point 2, the maximum flow depth decreases by 49.7% with an open-type check dam and 77.4% with a closed-type check dam. Thus, this study suggests that the simple installation of check dams in a mountain stream that has experienced debris flow effectively mitigates damage brought by various disasters.

scholarly journals Study on the Impact Resistance of Metal Flexible Net to Rock fall

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Gaosheng Wang ◽  
Yunhou Sun ◽  
Ao Zhang ◽  
Lei Zheng ◽  
Yuzheng Lv ◽  
...  
Keyword(s):  
Finite Element ◽  
Impact Force ◽  
Impact Resistance ◽  
Time History ◽  
Rock Fall ◽  
Fe Model ◽  
Element Analysis ◽  
Inclination Angles ◽  
Fall Protection ◽  
The Impact

Based on experiments and finite element analysis, the impact resistance of metal flexible net was studied, which can provide reference for the application of metal flexible net in rock fall protection. The oblique (30 degrees) impact experiment of metal flexible net was carried out, the corresponding finite element (FE) to the experiment was established, and the FE model was verified by simulation results to the experimental tests from three aspects: the deformation characteristics of metal flexible net, the time history curves of impact force on supporting ropes, and the maximum instantaneous impact force on supporting ropes. The FE models of metal flexible nets with inclination angles of 0, 15, 30, 45, 60, and 75 degrees were established, and the impact resistance of metal flexible nets with different inclination angles was analyzed. The research shows that the metal flexible net with proper inclination can bounce the impact rock fall out of the safe area and prevent rock fall falling on the metal flexible net, thus realizing the self-cleaning function. When the inclination angle of the metal flexible net is 15, 30, and 45 degrees, respectively, the bounce effect after impact is better, the remaining height is improved, the protection width is improved obviously, and the impact force is reduced. Herein, the impact force of rock fall decreases most obviously at 45 degrees inclination, and the protective performance is relatively good.

Finite Element Analysis of a Single-Layer Reticulated Dome under Impact Loading

2010 ◽  
Vol 163-167 ◽  
pp. 327-331 ◽  
Author(s):  
Liang Zheng ◽  
Zhi Hua Chen
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Impact Force ◽  
Impact Load ◽  
Residual Deformation ◽  
Time History ◽  
Single Layer ◽  
Element Analysis ◽  
Deformation Stage ◽  
The Impact

Finite element model of both the single-layer Schwedler reticulated dome with the span of 50m and a Cuboid impactor were developed, incorporating ANSYS/LS-DYNA. PLASTIC_KINEMATIC (MAT_003) material model which takes stain rate into account was used to simulate steel under impact load. The automatic point to surface contact (NODES TO SURFACE) was applied between the dome and impact block. Three stages of time history curve of the impact force on the apex of the single-layer Scheduler reticulated dome including the impact stage, stable stalemate stage, the decaying stage were generalized according to its dynamic response. It must be pointed out that the peak of the impact force of the single-layer reticulated dome increase with the increase of the weight and the velocity of the impact block, but the change of the velocity of the impact block is more sensitive than the change of weight of the impact block for the effect of the peak of the impact force, and a platform value of the impact force of the single-layer reticulated dome change near a certain value, and the duration time of the impact gradually increase. Then four stages of time history curve of the impact displacement were proposed according to the dynamic response of impact on the apex of the single-layer reticulated dome based on numerical analysis. Four stages include in elastic deformation stage, plastic deformation stage, elastic rebound stage, free vibration stage in the position of the residual deformation.

Numerical Simulation and Experimental Study on Fluid-Filled Hemispherical Shell under Impact

2013 ◽  
Vol 364 ◽  
pp. 172-176
Author(s):  
Hui Wei Yang ◽  
Bin Qin ◽  
Zhi Jun Han ◽  
Guo Yun Lu
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
Impact Load ◽  
Elastic Recovery ◽  
Plastic Hinge ◽  
Time History ◽  
Hemispherical Shell ◽  
History Of ◽  
Local Impact ◽  
The Impact

The dynamic response of fluid-filled hemispherical shell in mass impact is studied by experiment using DHR9401. Combining the time history of impact force with experimental observation of the deformation process, it can be seen that the dynamic response can be divided into four stages: the flattening around the impact point, the forming and expanding outward of shell plastic hinge, the plastic edge region flatten by the punch, and elastic recovery. The experimental results show that: Because the shell filled with liquid, the local impact load that the shell suffered is translated into area load and loads on the inner shell uniformly, so that it has a high carrying capacity. Numerical simulation is used to study the time history of energy absorption of different shell structures. The result shows that the crashworthiness of sandwich fluid-filled shell is improved greatly. Under the certain impact energy, deformation of its inner shell is very small, which can provide effective security space.

ESTIMATION OF IMPACT LOAD IN THICK PLATE BY USING THEORETICAL GREEN FUNCTION AND EXPERIMENTAL MEASUREMENT OF VIBRATION

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1377-1382
Author(s):  
H. W. Kim ◽  
S. K. Lee
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Thick Plate ◽  
Impact Load ◽  
Plate Theory ◽  
Time History ◽  
Force Transducer ◽  
Good Prediction ◽  
History Of ◽  
The Impact

The classic plate theory (CPT) as a theoretical solution to an impact load has been used in a thin plate. However, The CPT is not any more useful solution for the impact load in the industrial power plant, which is generally constructed by the thick plate. In this paper a novel and effective approach is developed to determine the time history of the impact load on a thick aluminum plate based on the analysis of the acoustic waveforms measured by a sensor array located on the thick plate surface in combination with the theoretical Green's function for the plate. The Green's functions are derived based on either the exact elastodynamic or theory the approximate shear deformation plate theory (SDPT). If the displacement is measured on the plate, then the time history of impact load can be calculated by deconvolving the measured displacement with the theoretical Green's function. The reconstructed time history for impact load is compared with the time history of the impact load measured by the force transducer. A good prediction is found. This technique presents a valuable method for identification of source and may be applied to in-service structures under impact to signals recorded from acoustic emission of propagating cracks.

scholarly journals Numerical simulation of 2D hydrodynamic impact of wedge and ship section at variable velocity

2013 ◽  
Vol 10 (1) ◽  
pp. 49-58 ◽  
Author(s):  
Md. Mashiur Rahaman ◽  
Hiromichi Akimoto ◽  
Md. Ashim Ali
Keyword(s):  
Impact Load ◽  
Time History ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Variable Velocity ◽  
History Of ◽  
Volume Method ◽  
The Impact ◽  
Simulated Time ◽  
Simulated Flow

A commercial CFD code Fluent 6.3® is used to simulate non-linear free surface flow and compute the impact load during variable velocity water entry of 2D wedge and ship section. The code uses the finite volume method to solve the conservation of mass and momentum equations to obtain simulated flow field. The interface between water and air was modeled using volume of fluid (VOF) method. Wedge section with 30 degree dead-rise angle and a ship section are numerically simulated. Time history of impact force and pressures at distinct locations are predicted; and compared with existing experimental results and other numerical methods. Present numerical results compare well with experimental measurements.DOI: http://dx.doi.org/10.3329/jname.v10i1.14383

scholarly journals Dynamic Response Analysis of Retaining Dam under the Impact of Solid-Liquid Two-Phase Debris Flow Based on the Coupled SPH-DEM-FEM Method

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Bailong Li ◽  
Changming Wang ◽  
Yanying Li ◽  
Yiao Liu ◽  
Nan Jiang ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Debris Flow ◽  
Impact Force ◽  
Time History ◽  
Impact Behavior ◽  
Response Analysis ◽  
Two Phase ◽  
Fem Method ◽  
Solid Liquid ◽  
The Impact

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.

scholarly journals The Influence of an EPS Concrete Buffer Layer Thickness on Debris Dams Impacted by Massive Stones in the Debris Flow

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Xianbin Yu ◽  
Xiaoqing Chen ◽  
Wanyu Zhao ◽  
Jiangang Chen
Keyword(s):  
Debris Flow ◽  
Buffer Layer ◽  
Structural Design ◽  
Impact Force ◽  
Three Dimensional ◽  
Time History ◽  
Expanded Polystyrene ◽  
Debris Dams ◽  
The Impact ◽  
Debris Dam

The failure of debris dams impacted by the massive stones in a debris flow represents a difficult design problem. Reasonable materials selection and structural design can effectively improve the resistance impact performance of debris dams. Based on the cushioning properties of expanded polystyrene (EPS) concrete, EPS concrete as a buffer layer poured on the surface of a rigid debris dam was proposed. A three-dimensional numerical calculation model of an EPS concrete buffer layer/rigid debris dam was established. The single-factor theory revealed change rules for the thickness of the buffer layer concerning the maximal impact force of the rigid debris dam surface through numerical simulation. Moreover, the impact force-time/history curves under different calculation conditions for the rigid debris dam surface were compared. Simulation results showed that the EPS concrete buffer layer can not only effectively extend the impact time of massive stones affecting the debris dam but also reduce the impact force of the rigid debris dam caused by massive stones in the debris flow. The research results provide theoretical guidance for transferring the energy of the massive stone impact, creating a structural design and optimizing debris dams.

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