Numerical Analysis on Failure Behavior of Composite Sandwich Plate

2013 ◽  
Vol 284-287 ◽  
pp. 178-182
Author(s):  
Yao Hsu

The Composite sandwich plate is made of two laminated face-sheets and one core material. Since such a kind of structure has many advantages, they have been widely used in structural manufacturing industry. However, when sandwich plates are impacted by transverse loadings, damages that are usually invisible would occur inside the sandwich plate and those damages would potentially reduce the structural safety. Therefore, it is necessary to elucidate the failure mechanism and how they affect the failure behaviors of sandwich structures for safety purpose. To this end, the present study is to investigate the impact failure behaviors of sandwich plates subjected to a rigid spherical impactor. Numerical simulation approach is carried out by finite element method. To predict the initial failure, several failure criteria to face-sheets and core material are proposed. In addition, to further simulate the progressive failure behaviors, a stiffness modification method is proposed and incorporated into the finite element software. The analytical results show that the local failure including fiber breakages, delamination, core cracking and plasticity is the main failure mechanism of cases studied. Furthermore, parametric study is also conducted and discussed in the paper.

2018 ◽  
Vol 22 (8) ◽  
pp. 2818-2860 ◽  
Author(s):  
Paul Praveen A ◽  
Vasudevan Rajamohan ◽  
Ananda Babu Arumugam ◽  
Arun Tom Mathew

In the present study, the free and forced vibration responses of the composite sandwich plate with carbon nanotube reinforced honeycomb as the core material and laminated composite plates as the top and bottom face sheets are investigated. The governing equations of motion of hybrid composite honeycomb sandwich plates are derived using higher order shear deformation theory and solved numerically using a four-noded rectangular finite element with nine degrees of freedom at each node. Further, various elastic properties of honeycomb core materials with and without reinforcement of carbon nanotube and face materials are evaluated experimentally using the alternative dynamic approach. The effectiveness of the finite element formulation is demonstrated by performing the results evaluated experimentally on a prototype composite sandwich plate with and without carbon nanotube reinforcement in core material. Various parametric studies are performed numerically to study the effects of carbon nanotube wt% in core material, core thickness, ply orientations, and various boundary conditions on the dynamic properties of composite honeycomb sandwich plate. Further, the transverse vibration responses of hybrid composite sandwich plates under harmonic force excitation are analyzed at various wt% of carbon nanotubes and the results are compared with those obtained without addition of carbon nanotubes to demonstrate the effectiveness of carbon nanotube reinforcement in enhancing the stiffness and damping characteristics of the structures. The study provides the guidelines for the designer on enhancing both the stiffness and damping properties of sandwich structures through carbon nanotube reinforcement in core materials.


2017 ◽  
Vol 1143 ◽  
pp. 139-144 ◽  
Author(s):  
Florentina Rotaru ◽  
Ionel Chirica ◽  
Elena Felicia Beznea

In this paper the influence cell honeycomb geometry on the mechanical behaviour of a composite sandwich plate is analyzed. Three cell geometries (circular, hexagonal and square) are static analysed so that to select the best type of honeycomb that will be used in the manufacturing the sandwich plate core. The main aim is to develop approach models of equivalent orthotropic materials to replace the real model of honeycomb core with their properties so that to quickly calculate the sandwich plate made out of composite when is used a finite element analysis code. Geometry and material properties of the honeycomb are delivered by the material provider. Comparative analysis, by using Finite element analysis is performed for all geometries, in the same boundary conditions. Since in the impact loading of the composite sandwich plate the core is mainly loaded to compression, comparative study of the three cell geometries honeycomb was performed for this type of compressive loading. Since the cell is the basic element of the honeycomb core, the calculus is performed for one unit volume of sandwich, concerning also the part of skins.


2011 ◽  
Vol 121-126 ◽  
pp. 316-319
Author(s):  
Ivan Yao Hsu

Due to many of advantages such as lightweighted, high-bending mechanical characteristics, composite sandwich materials play an important role in today’s structural manufacturing industry. This study is to aim at the low-velocity impact responses of sandwich plates subjected to a rigid, spherical-shaped impactor. The sandwich made of PVC core material (two kinds of core with different densities) and FRP facesheets (three kinds of fibrous laminae) were investigated experimentally and numerically. Because the dynamic behaviors of specimens due to low velocity impact is nearly the same to those in static indentation, the impact failure analysis of sandwich material can be simulated statically. Beside the experiment, finite element method was employed to analyze the static failure behaviors of sandwich panels. With the maximum stress failure criterion as well as a modified stiffness degradation method coded in the finite element software, the initial failure and sequential progressive failure process can be analyzed effectively.


Author(s):  
E. Nazari ◽  
B. Shekastehband

The dynamic failure behavior of double-layer-domes subjected to impact is studied numerically through the nonlinear finite element software LS-DYNA. The parameters considered in this work include the mass, velocity, and size of impactor, impact direction, roof weigh, geometric imperfection, rise-to-span ratio, and depth of dome. The dynamic time-history response and energy conversion of the structure are utilized to distinguish between the failure mechanism types. For the cases studied, it is found that failure of the structures falls into one of the three categories: (1) local shear failure, (2) partial progressive failure, and (3) full progressive failure. Non-failure case dominates the dome response when the kinetic energy of the impactor is small enough, and the structure can convert most of the kinetic energy into the strain energy, thereby absorbing the impact. Local shear failure occurs in a double-layer-dome when an impactor with very high kinetic energy strikes the dome. For an impactor striking with a mass of 5 to 300[Formula: see text]ton and a velocity of 50 to 120[Formula: see text]m/s, the double-layer-dome studied will suffer from partial progressive failure. Varying mass and velocity of the impactor in the range of 1 to 300[Formula: see text]ton and 200 to 400[Formula: see text]m/s, respectively, results in a tendency of the dome to exhibit local shear failure. Although impact direction does not cause a change in the failure mechanism type, there is a reduction in the severity of failure of the system as the impact angle increases. Roof weight has no dominant effect on the failure mechanism of the double-layer-dome. A small initial member imperfection with amplitude 0.001[Formula: see text] does not change the progressive failure type. A large member imperfection of 0.01[Formula: see text] triggers member buckling and leads to local shear failure of the dome. Except for some loading cases, the change in the rise to span ratio and depth of the dome does not seriously affect the failure mode.


2006 ◽  
Vol 22 (3) ◽  
pp. 213-220 ◽  
Author(s):  
K. J. Shou ◽  
F. W. Chang

AbstractIn this study, physical and numerical models were used to analyze pipe-soil interaction during pipejacking work. After calibrating with the physical modeling results, the finite element software ABAQUS [1] was used to study the pipejacking related behavior, such as surface subsidence, failure mechanism, pipe-soil interaction, etc. The results show that the driving force in the tunnelling face is very important and critical for pipejacking. Surface subsidence is mainly due to the lack of driving force, however, excessive driving force could cause the unfavorable surface heaving problem. It also suggests that the depth of the pipe is critical to determine a proper driving force to stabilize the tunnelling face.


Author(s):  
Yaogang Wu ◽  
Zhengguang Xiao ◽  
Kangwei Liu ◽  
Dinghe Li

An Extended Layerwise/Solid-Element (XLW/SE) method is developed based on the Extended Layerwise method (XLWM) and eight-node solid element method for the static analysis of damaged composite sandwich structures with piezoelectric sensor. In this method, the XLWM is used to model the facesheets and piezoelectric sensors, and the eight-node solid element is used for the lattice. Based on the equilibrium conditions of displacement and internal force of the overlapped joints at the facesheet/sensors and facesheet/lattice interfaces, the general governing equation is established. In the numerical examples, the proposed method is verified by comparing with the 3D elasticity model developed in the commercial finite element software, and composite sandwich plates with delamination and/or transverse crack and/or debonding are analyzed.


2016 ◽  
Vol 5 (1) ◽  
pp. 232-249
Author(s):  
Riccardo Vescovini ◽  
Lorenzo Dozio

Abstract The analysis of monolithic and sandwich plates is illustrated for those cases where the boundary conditions are not uniform along the thickness direction, and run at a given position along the thickness direction. For instance, a sandwich plate constrained at the bottom or top face can be considered. The approach relies upon a sublaminate formulation,which is applied here in the context of a Ritz-based approach. Due to the possibility of dividing the structure into smaller portions, viz. the sublaminates, the constraints can be applied at any given location, providing a high degree of flexibility in modeling the boundary conditions. Penalty functions and Lagrange multipliers are introduced for this scope. Results are presented for free-vibration and bending problems. The close matching with highly refined finite element analyses reveals the accuracy of the proposed formulation in determining the vibration frequencies, as well as the internal stress distribution. Reference results are provided for future benchmarking purposes.


2021 ◽  
Vol 9 ◽  
Author(s):  
Jiaxiang Li ◽  
Biao Wang ◽  
Jian Sun ◽  
Shuhong Wang ◽  
Xiaohong Zhang ◽  
...  

Ice shedding causes transmission lines to vibrate violently, which induces a sharp increase in the longitudinal unbalanced tension of the lines, even resulting in the progressive collapse of transmission towers in serious cases, which is a common ice-based disaster for transmission tower-line systems. Based on the actual engineering characteristics of a 500 kV transmission line taken as the research object, a finite element model of a two-tower, three-line system is established by commercial ANSYS finite element software. In the modeling process, the uniform mode method is used to introduce the initial defects, and the collapse caused by ice shedding and its influencing parameters are systematically studied. The results show that the higher the ice-shedding height is, the greater the threat of ice shedding to the system; furthermore, the greater the span is, the shorter the insulator length and the greater the dynamic response of the line; the impact of ice shedding should be considered in the design of transmission towers.


2013 ◽  
Vol 639-640 ◽  
pp. 593-597
Author(s):  
Lin Chen ◽  
Yong Yao ◽  
Jiong Yang ◽  
Zhao Qiang Zhang

According to finite element strength reduction method,the article has discussed the failure mechanism of anti-sliding pile by using finite element software MIDAS /GTS ,exploration report and anti-sliding pile design data.The comparative analysis shows that the failure of anti-siding pile is contributed by the slope excavation and rainwater.The analysis method and results can provide reference significance to other anti-sliding pile design.This paper also provide a feasible method for prediction of consequence in slope excavation.


2013 ◽  
Vol 405-408 ◽  
pp. 3243-3247
Author(s):  
Wei Su ◽  
Ying Sun ◽  
Shi Qing Huang ◽  
Ren Huai Liu

In this paper, the structural safety of the Niuwan Bridge subjected to vessel collision is investigated by the large-scale commercial finite element software ANSYS. A whole FEM model is built and a reasonable analysis and illustration for taking the value of vessel-collision forces is presented. Additionally, under the premise of reasonable simulation of the boundary conditions, the effects of the support abutments, the prestress and the carloads are considered. The analysis results have certain reference values for the anti-collision and reinforcement of bridges.


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