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Quasimolecular Dynamic Simulation for Bending Fracture of Laminar Composite Materials

Youngsuk Kim,Youngmoon Lee,Dongyoul Choi,Chanil Kim,

材料科学技术学报 , 2001,
Abstract: Recently, quasimolecular dynamics has been successfully used to simulate the deformation characteristics of actual size solid materials. In quasimolecular dynamics, which is an attempt to bridge the gap between atomistic and continuum simulations, molecules are aggregated into large units, called quasimolecules, to evaluate large scale material behavior. In this paper, a 2-dimensional numerical simulation using quasimolecular dynamics was performed to investigate laminar composite material fractures and crack propagation behavior in the uniform bending of laminar composite materials. It was verified that under bending deformation laminar composite materials deform quite differently from homogeneous materials.
Identification of composite materials at high speed deformation with the use of degenerated model  [PDF]
K. Jamroziak,M. Bocian
Journal of Achievements in Materials and Manufacturing Engineering , 2008,
Abstract: Purpose: Composite materials on account of some their characteristics have application in a construction of ballistic shield. An example of the ballistic shield is laminate with the mix-structure materials such as layer pressed of aramid cloths on matrix polymer. Because of the shield’s assignment the aramid cloths are exposed to impact loads caused by an energy made by impact force of cumulated mass (bullet). Previous analyses of the effect are based on linear-elastic reaction of resisting forces between the materials of a bullet and a shield. The article exemplifies the procedure of mechanical properties analysis in the punch effect of the ballistic shield with the use of some of the non-elastic models.Design/methodology/approach: In the article the theoretical analysis of punch effect in the quasi-static load condition based on some of the degenerated models is also presented.Findings: The results of the analysis make aware of demand for designing safety ballistic shields.Research limitations/implications: The main conception was optimum material selection (composite) that has to be done according to the theoretical analysis, which is based on non-elastic models selected in the context of velocity and mass of punching bullet.Practical implications: Application of the complex degenerated model allows to define more characteristics of the punching process of the ballistic shield. Determination of the effect of energy impact dissipation causes material damage of the ballistic shield is enabled to do because of implementation of boundary conditions.Originality/value: Based on the boundary conditions of energy in the way of changing parameters of model we are able to describe non-destructive deformation process.
Bending analysis of composite laminated plates using higher-order shear deformation theory with zig-zag function  [PDF]
T. Dharma Raju,J. Suresh Kumar
Journal of Engineering and Applied Sciences , 2011,
Abstract: In this paper an analytical procedure is developed, to investigate the bending characteristics of laminated composite plates based on higher order shear displacement model with zig-zag function. This zig-zag function improves slope discontinuities at the interfaces of laminated composite plates. The equation of motion is obtained using the dynamic version of Hamilton’s principle. The solutions are obtained using Navier’s and numerical methods for anti-symmetric cross-ply and angle-ply laminates with a specific type of simply supported boundary conditions SS-1 and SS-2 respectively. In this paper the Numerical results are presented for bending of anti-symmetric cross-ply and angle-ply laminated plates. All the solutions presented are close agreement with the theory of elasticity and closed form solutions available in the literature.
Dynamic tensile deformation and fracture of a highly particle-filled composite using SHPB and high-speed DIC method  [cached]
Zhou Z.,Chen P.,Guo B.,Huang F.
EPJ Web of Conferences , 2012, DOI: 10.1051/epjconf/20122601005
Abstract: In this work, various tensile tests, including Brazilian disc test (BDT), flattened Brazilian disc (FBD) test and semi-circular bending (SCB) test, were carried out on a highly particle-filled composite by using a split Hopkinson pressure bar (SHPB). With the consideration of low strength and low wave impedance of the materials, a quartz crystal transducer was embedded in SHPB to measure the loading forces. A high-speed camera was used to capture the deformation and fracture process of materials. Digital image correlation (DIC) method was used to process these digital images to obtain the dynamic deformation information. Based on the measured strain fields, the crack growth path was determined and the failure mechanism of samples was analyzed. Combining SHPB and DIC method, the indirect tensile stress strain plots of disc samples were obtained, and the dynamic fracture toughness of materials was measured using both FBD and SCB tests. The results show that the tensile failure strength and fracture toughness increases with the increase of strain rates, exhibiting strain rate dependence. The high-speed DIC method combined with SHPB is effective to study the dynamic tensile behaviour of brittle materials with low strengths.
A New Hyperbolic Shear Deformation Theory for Bending Analysis of Functionally Graded Plates  [PDF]
Tahar Hassaine Daouadji,Abdelaziz Hadj Henni,Abdelouahed Tounsi,Adda Bedia El Abbes
Modelling and Simulation in Engineering , 2012, DOI: 10.1155/2012/159806
Abstract: Theoretical formulation, Navier’s solutions of rectangular plates based on a new higher order shear deformation model are presented for the static response of functionally graded plates. This theory enforces traction-free boundary conditions at plate surfaces. Shear correction factors are not required because a correct representation of transverse shearing strain is given. Unlike any other theory, the number of unknown functions involved is only four, as against five in case of other shear deformation theories. The mechanical properties of the plate are assumed to vary continuously in the thickness direction by a simple power-law distribution in terms of the volume fractions of the constituents. Numerical illustrations concern flexural behavior of FG plates with metal-ceramic composition. Parametric studies are performed for varying ceramic volume fraction, volume fractions profiles, aspect ratios, and length to thickness ratios. Results are verified with available results in the literature. It can be concluded that the proposed theory is accurate and simple in solving the static bending behavior of functionally graded plates. 1. Introduction The concept of functionally graded materials (FGMs) was first introduced in 1984 by a group of material scientists in Japan, as ultrahigh temperature-resistant materials for aircraft, space vehicles, and other engineering applications. Functionally graded materials (FGMs) are new composite materials in which the microstructural details are spatially varied through nonuniform distribution of the reinforcement phase. This is achieved by using reinforcement with different properties, sizes, and shapes, as well as by interchanging the role of reinforcement and matrix phase in a continuous manner. The result is a microstructure that produces continuous or smooth change on thermal and mechanical properties at the macroscopic or continuum level (Koizumi, 1993 [1]; Hirai and Chen, 1999 [2]). Now, FGMs are developed for general use as structural components in extremely high-temperature environments. Therefore, it is important to study the wave propagation of functionally graded materials structures in terms of nondestructive evaluation and material characterization. Several studies have been performed to analyze the mechanical or the thermal or the thermomechanical responses of FG plates and shells. A comprehensive review is done by Tanigawa (1995) [3]. Reddy (2000) [4] has analyzed the static behavior of functionally graded rectangular plates based on his third-order shear deformation plate theory. Cheng and Batra (2000)
High-cycle bending fatigue and life prediction of composite materials

- , 2018, DOI: 10.13801/j.cnki.fhclxb.20180319.007
Abstract: 利用一阶弯曲共振现象,开展了复合材料悬臂梁高周弯曲疲劳试验。为了取代传统的金属疲劳理论,根据复合材料疲劳损伤渐进扩展的特点,发展了新的数值方法应用于复合材料的疲劳分析。研究局部疲劳损伤模型和周期跳跃技术,开发了复合材料悬臂梁高周弯曲疲劳的半解析法Matlab疲劳损伤分析程序;另一方面,通过开发UMAT子程序,实现了疲劳损伤模型和周期跳跃技术在商业有限元软件ABAQUS中的应用。分别使用半解析法和有限元法分析复合材料悬臂梁高周弯曲疲劳的损伤累积破坏过程,预测了其高周弯曲疲劳寿命,数值预测结果与试验结果较好吻合。 The high-cycle bending fatigue experiment of composite cantilever beam was designed by employing the first-order bending resonance phenomenon. Based on the study of the local fatigue damage model and cycle jump technique, the Matlab-based semi-analytical algorithm for high-cycle bending fatigue analysis of the composite cantilever beam was developed to substitute for traditional metal fatigue theory. On the other hand, on the basis of UMAT subroutine, the fatigue damage model and cycle jump technology were successfully applied in the commercial software ABAQUS. The semi-analytical method and the finite element method were separately employed to analyze the progressive damage accumulation and failure process for the high-cycle bending fatigue, out of which high-cycle bending fatigue life was predicted. The numerical results are in agreement with the experimental data. 国家自然科学基金(51675024;51375031;51811540406)
FEM Simulation of Bending Formability for Laminate Steel/Resin/Steel Lightweight Composite Sheet
FEM Simulation of Bending Formability for Laminate Steel/Resin/Steel Lightweight Composite Sheet

Guancheng LI,Yonglin KANG,

材料科学技术学报 , 2003,
Abstract: The ANSYS simulation software was used to analyze the bending formability of laminate steel/resin/steel lightweight composite sheet. The skin steel at external side produces relative slipping-off change during the bending due to its composite structure. The internal stress strain states, materials effect tools parameters and intermediate layer resin of lightweight sheet on slipping-off change were analyzed. The spring back and shear stress state after bending have also been discussed.
Bending and Deformation of Sandwich Panels Due to Localized Pressure
Bambang K. Hadi,A. Fajar
ITB Journal of Engineering Science , 2005,
Abstract: Bending and deformation of sandwich panels due to localized pressure were analyzed using both Rayleigh-Ritz and finite element methods. The faces were made of laminated composite plates, while the core was a honeycomb material. Carbon fiber and glass fiber reinforced plastics were used for composite plate faces. In the case of Rayleigh-Ritz method, first the total energy of the system was calculated and then taking the variations of the total energy, the sandwich panel deflections could be computed. The deflections were assumed by means of Fourier series. A finite element code NASTRAN was exploited extensively in the finite element method. 3-dimensional 8-node brick elements were used to model sandwich panels, for both the faces sheets and the core. The results were then compared to each other and in general they are in good agreements. Dimple phenomena were found in these cases. It shows that localized pressure on sandwich structures will produce dimple on the pressurize region with little effects on the rest of the structures.
Efficiency of twist deformation of composite plate actuated by MFC

- , 2018, DOI: 10.13700/j.bh.1001-5965.2017.0107
Abstract: 摘要 含有主动材料的复合结构越来越多地应用于自适应结构中。主动纤维材料的应用为复合结构带来了新的特性也使其设计更为复杂。针对受压电纤维材料(MFC)驱动的主动材料复合板的变形进行研究,目的在于获得MFC驱动复合板扭曲变形与MFC纤维铺设及驱动模式的关系。基于弹性力学理论建立了受电压作用主动纤维产生的应变与由此导致的复合板的内力、变形之间的关系,并利用Ritz法,通过假设双向梁函数组合级数的位移场建立了该问题的求解方法,经推导得到了MFC驱动下位移场的求解方程,实验结果验证了其有效性。为了评估MFC驱动复合板在不同条件下的驱动效果,针对复合板变形所具有的弯扭耦合特点,在定义复合板截面等效扭转角和等效弯曲角的基础上提出了主动复合板驱动扭曲变形效率的概念和计算方法,利用该方法分析了MFC的铺设角度以及电压驱动模式对复合板扭曲变形效率的影响。依据分析所得到的结果给出了对应不同约束条件的MFC驱动复合板主动纤维布置及驱动模式的选择方案。
Abstract:More and more composite structures containing active materials are applied to adaptive structures. The integration of active materials in structures has brought new characteristics but made the design more complicated. In this paper, the deformation of the active composite plate actuated by the macro fiber material (MFC) is studied. The purpose is to obtain the relationship between the twist deformation of the actuated composite plate and the MFC fiber laying and the actuation mode. Based on the elastic mechanics theory, the relationship between the strain of active fiber actuated by voltage and induced internal force and deformation of the composite plate is established. The solution of the problem is conducted using Ritz's method and taking the displacement function as a linear combination of the two-dimension beam-modes. The solving equation of the displacement field actuated by MFC is derived, and the analytical result is verified by the experiment. In order to evaluate the actuation effect of MFC composite plate under different conditions and to consider the bending-torsion coupling characteristics of composite plate deformation, the concept and the calculation of actuation efficiency of an active composite plate are proposed, which is based on the definition of equivalent bending and twist angle of section. Then the evolution of the actuation efficiency with the laying angle of MFC and the mode of input voltage is analyzed. Corresponding to different constraint conditions, the laying of piezoelectric fiber-direction and the selection of actuation-mode are given based on the obtained analysis results.
Multi-axial load application and DIC measurement of advanced composite beam deformation behavior  [cached]
Fedorov V.,Berggreen C.
EPJ Web of Conferences , 2010, DOI: 10.1051/epjconf/20100616006
Abstract: For the validation of a new beam element formulation, a wide set of experimental data consisting of deformation patterns obtained for a number of specially designed composite beam elements, have been obtained. The composite materials applied in the beams consist of glass-fiber reinforced plastic with specially designed layup configurations promoting advanced coupling behavior. Furthermore, the beams are designed with different cross-section shapes. The data obtained from the experiments are also used in order to improve the general understanding related to practical implementation of mechanisms of elastic couplings due to anisotropic properties of composite materials. The knowledge gained from these experiments is therefore essential in order to facilitate an implementation of passive control in future large wind turbine blades. A test setup based on a four-column MTS servo-hydraulic testing machine with a maximum capacity of 100 kN was developed, see Figure 1. The setup allows installing and testing beams of different cross-sections applying load cases such as axial extension, shear force bending, pure bending in two principal directions as well as pure torsion, see Figure 2. In order to apply multi-axial loading, a load application system consisting of three hydraulic actuators were mounted in two planes using multi-axial servo-hydraulic control. The actuator setup consists of the main actuator on the servo-hydraulic test machine working in the vertical axis (depicted on Figure 1) placed at the testing machine crosshead and used for application of vertical forces to the specimens. Two extra actuators are placed in a horizontal plane on the T-slot table of the test machine in different positions in order to apply loading at the tip of the specimen in various configurations. In order to precisely characterize the global as well as surface deformations of the beam specimens tested, a combination of different measurement systems were used during the tests. Digital Image Correlation (DIC) systems [1] able to measure the 3D displacement field along the specimen surface were applied. Two linked DIC systems were used simultaneously during the experiments in order to obtain measurements for most of the surface of the beams. Additionally, an optical system based on mirrors and laser beams allowing direct measuring of the twist along the specimen were applied as well. Results from both systems were additionally used to verify obtained results. A number of FE models with different modeling approaches were furthermore developed for each specimen type and validated
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