Hailstone-induced dynamic responses of pretensioned umbrella membrane structure

2020 ◽  
Vol 24 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Changjiang Liu ◽  
Fan Wang ◽  
Xiaowei Deng ◽  
Song Pang ◽  
Jian Liu ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Membrane Structure ◽  
Impact Analysis ◽  
Impact Load ◽  
Dynamic Responses ◽  
Flexible Structure ◽  
Membrane Material ◽  
Membrane Structures ◽  
Characteristic Points ◽  
The Impact

The membrane structure is a flexible structure, which is easy to vibrate or even relax under dynamic load. Engineering accident analysis shows that the relaxation of membrane structure is more likely to lead to structural failure. In this article, the impact load problem is combined with the flexible structure to analyze the impact of hailstone impact load on the dynamic response of membrane structure. First, the umbrella membrane stretching device was designed and manufactured, and the hailstone impact test was carried out on the umbrella membrane structure with polyvinyl chloride membrane material. Dynamic response data, tension relaxation of side cables and vibration deformation of umbrella membrane structures impacted by hailstones with different sizes and different characteristic points were obtained. In the numerical analysis, the form-finding analysis of umbrella membrane structure is carried out by finite element method, and the transient impact analysis is conducted in LS-DYNA. Finally, the reliability of the research results is verified by comparing the numerical and experimental results. The general laws and conclusions are drawn and the disaster-causing mechanism of membrane structure impacted by hailstone is revealed. On the whole, although the probability of hailstone destroying the membrane material directly is very small, it will relax the membrane structure and affect the safety of membrane structure. The conclusions of this article provide a theoretical basis for the design and maintenance of membrane structures.

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.

Simulation of Failure of a Fixed Beam Subjected to Impact Load Using Quadrilateral Discrete Element Method

2012 ◽  
Author(s):  
Rajesh P. Nair ◽  
C. Lakshmana Rao
Keyword(s):  
Discrete Element Method ◽  
Impact Analysis ◽  
Mechanical Response ◽  
Impact Load ◽  
Discrete Element ◽  
Failure Criteria ◽  
Discrete Elements ◽  
The Impact ◽  
Fixed Beam ◽  
Element Method

Discrete Element Method (DEM) is an explicit numerical scheme to model the mechanical response of solid and particulate media. In our paper, we are introducing Quadrilateral Discrete Element Method (QDEM) for the simulation of the separation of elements in fixed beam subjected to impact load. QDEM results are compared with other DEM results available in literature. Impact loads include two cases: (a) a half sine wave and (b) a penetrator hitting the fixed beam. Separation criteria used for the discrete elements is maximum principal stress failure criteria. In QDEM, convergence study for the response of fixed beam is obtained using MATLAB platform. Validation of quadrilateral elements in fixed beam is being carried out by comparing the results with empirical formula available in literature for the impact analysis.

Analysis of Dynamic Response of Mine Rescue Chamber under Axial Impact Load

2011 ◽  
Vol 211-212 ◽  
pp. 576-580 ◽  
Author(s):  
Ming Song ◽  
Shi Rong Ge ◽  
Hai Feng Fang
Keyword(s):  
Dynamic Response ◽  
Impact Load ◽  
Element Model ◽  
Deformation Energy ◽  
Spherical Shells ◽  
Tunnel Wall ◽  
Axial Impact ◽  
Plate And Shell ◽  
The Impact ◽  
Mine Rescue

In order to research the problem of rescue chamber colliding with the tunnel wall. The theoretical model of rescue chamber has been formed, based on the principle of energy conservation, by using theories of plates and shells, large deformed plate and shell, and by analysis of dynamic response of mine rescue chamber under axial impact load. This model includes initial velocity, contact force deformation energy and shell deformation. Dytran software was applied to build the finite element model of the rescue chamber contacting the rigid plate. Through comparison emulation result and theoretical analysis result, this model is proved to be highly reliable. The theoretical calculation and the simulation indicated that there were obvious relationships among the ability of the mine rescue chamber under axial impact load with the thickness, depth of flat spherical shells. If the thickness or depth increases, then the chamber could stand more. It is also confirmed that increasing the depth of flat spherical shells can minish the impact force for making impact process abate, which provides a basis for the research of rescue chamber.

Analysis on the Effect of Input Impact Profiles in Drop Test

2007 ◽  
Author(s):  
Jiang Zhou ◽  
Ratna P. Niraula ◽  
Kendrick Aung
Keyword(s):  
Dynamic Response ◽  
Impact Load ◽  
Block Diagram ◽  
Input Pulse ◽  
Drop Test ◽  
System Level ◽  
System Response ◽  
Time Duration ◽  
Board Level ◽  
The Impact

The objective of this paper is to develop an analytical or mathematical predicative model for the evaluation of dynamic response of a structural element in a microelectronic or an optoelectronic product to an impact load occurring as a result of drop or shock test. Closed-form theoretical solution was obtained to simulate the board level drop test. The block diagram based SIMULINK analysis was introduced to determine the response with various impact configurations for the system level drop test as well. This study will help reliability engineers to design the impact input profiles and obtain the desired responses, and to calibrate and validate finite element analysis results quickly for both board level and system level drop test. It was found that time durations of the input profiles play an important role in the dynamic response. The system response can be designed by carefully choosing the impact time duration. Certain input pulse time results in the response with very low ringing after first or second peaks.

Impact Mechanics of Football Helmet with Various Shell Liner Configurations

2019 ◽  
Vol 32 ◽  
pp. 27-39
Author(s):  
Theddeus T. Akano ◽  
Omotayo Abayomi Fakinlede
Keyword(s):  
Finite Element ◽  
Impact Load ◽  
Dynamic Responses ◽  
Von Mises Stress ◽  
Elastoplastic Material ◽  
Composite Liner ◽  
Explicit Finite Element ◽  
Absorption Increase ◽  
Football Helmet ◽  
The Impact

The structure of the skull reveals that the cranial is made up of a number of bones. These bones, except the temporomandibular joint, are joined by sutures. The adjacent bones are strongly united by a matrix of connective tissues consisting of bundles of strong collagenous fibres connecting periosteum to the bones. The little movement at the sutures contributes to the elasticity and compliance of the cranial. This composition serves as a shock absorber and distributes impact force evenly around the skull. Frequent head impacts by footballers cause concussion which leads to brain and neurological disorders such as; Traumatic Brain Injury (TBI), dementia, depression, and a loss of attention span. These disorders are primarily caused by shock waves following impact, which moves from the front to the back of the brain. As such, the effort is geared at reducing head injuries from concussion by optimising helmet design through shock absorption increase and stress amplification reduction during impact. In this paper, the suture structure is mimicked in the design of a football helmet. A fibre-reinforced composite liner is introduced in the shell of the helmet. The liner runs from the front to the back of the helmet and bisects the shell into two equal parts. Hyperelastic material model is employed in the modelling of the composite liner while the polycarbonate helmet shell is modelled as a nonlinear elastoplastic material. A finite element model based on realistic geometric features of a football helmet was carried out, and an explicit finite element code LS-DYNA® is employed to simulate dynamic responses at different impact velocities of the helmet. The simulation was repeated for various compositions of the composite liner. Impact loads are applied on one side of the helmet shell while the responses are taken on the other side of the shell body of the helmet. To establish the validity of the model, the liner, and the shell materials are made to be the same. The results revealed that the responses of the helmet during impact are the same when the two components are of the same material compared with when there is no liner on the helmet shell. It was also shown that the dynamic response curve of the helmet emanating from different impacting conditions is judged by the maximum principal stress, Von Mises stress, and acceleration monitored within the impact period. The helmet composition with a sinusoidal liner form on the shell absorbed more impact load than other liner configurations.

scholarly journals Dynamic Model and Mechanical Properties of the Two Parallel-Connected CRLD Bolts Verified with the Impact Tensile Test

2018 ◽  
Vol 2018 ◽  
pp. 1-17
Author(s):  
Liangjun Hao ◽  
Weili Gong ◽  
Manchao He ◽  
Yanqi Song ◽  
Jiong Wang
Keyword(s):  
Dynamic Model ◽  
Impact Load ◽  
Tensile Tests ◽  
Dynamic Responses ◽  
Structural Deformation ◽  
Essential Difference ◽  
Support Design ◽  
The Impact ◽  
Theoretical Analyses ◽  
Theoretical Results

Dynamic model was theoretically established for the two parallel-connected constant-resistance-large-deformation (CRLD) bolts, and the theoretical results were experimentally verified with impact tensile tests on the CRLD bolts samples. The dynamic responses of the double CRLD bolts were investigated under the impact loads with different intensities. The theoretical analyses showed that (1) under relatively small loading the CRLD bolts deform elastically and the deformation finally returns to zero and (2) under the high impact load, including the stable impact load and unstable impact load, the CRLD bolts export structural deformation after the initial elastic deformation. The deformation of the bolts eventually stabilizes at a certain amount of the elongation caused by the relative sliding of the sleeves and rebars. The essential difference between the stable impact load and unstable impact load is that, under the stable impact load, no structural deformation will occur after the impact load ends; under the unstable impact load, the structural deformation will still occur after the impact load ends. The obtained results are of theoretical implications for rock support design with CRLD bolts under the dynamical loading condition.

scholarly journals Contact Dynamics and Stress Field of Fluid-Conveying GRC Nanotubes

2021 ◽  
Author(s):  
Qiduo Jin ◽  
Yiru Ren
Keyword(s):  
Stress Field ◽  
Dynamic Response ◽  
Strain Gradient ◽  
Time History ◽  
Contact Dynamics ◽  
Dynamic Responses ◽  
Stress And Strain ◽  
Nonlocal Stress ◽  
Post Buckling ◽  
The Impact

Abstract Fluid-conveying nanotubes play key roles in micro-nano electromechanical systems. The contact dynamic response and stress field of the fluid-conveying graphene reinforced composite (GRC) nanotube under lateral low-velocity impact are studied. The size-dependent models considering slip flow, nonlocal stress and strain gradient effect are established. The governing equations of flow-inducing post buckling and contact vibration are derived based on a refined beam theory, in which the post-buckling equilibrium provides the initial configuration for the impact vibration analysis. A computation mode of two-step perturbation-Galerkin truncation-Runge-Kutta method is developed to study the contact dynamic responses. Through the convergence analysis, the truncation terms required to ensure the accuracy are obtained. The contact force curves and the midspan displacement time history curves are acquired, and the dynamic snap-through instability behaviors of the nanotube in the flow-inducing post-buckling state are revealed. Also, the stress field in the impact process is obtained to provide theoretical results to guide the strength design. Numerical results reveal the dual influence law of nonlocal stress and strain gradient on the contact dynamic response and stress field and provide the flow velocity range sensitive to the nano effects.

Sign in / Sign up

Export Citation Format

Share Document