Progressive failure of 3-D-stressed laminates: Multiple nonlinearity treated by the failure mode concept (FMC)

2021 ◽  
pp. 3-27
Author(s):  
R.G. Cuntze
Keyword(s):  
Failure Mode ◽  
Progressive Failure

Numerical Analysis and Experimental Study of Carbon Fiber Reinforced Composite Joints under Bending Load

2021 ◽  
Vol 1163 ◽  
pp. 40-47
Author(s):  
Xi Lin Luo ◽  
Jian Hui Wei ◽  
Xue Kang Zhu ◽  
Hong Yin
Keyword(s):  
Failure Mode ◽  
Progressive Failure ◽  
Three Dimensional ◽  
Load Test ◽  
Bending Test ◽  
Displacement Curve ◽  
Composite Joints ◽  
Static Load Test ◽  
Bending Load ◽  
Load Displacement

Three dimensional finite element models of composite joints were established to investigate the load-displacement behavior, failure mode of multi-axial tubular joints under bending load, and stress-strain relationship in some key positions. The joints were prepared by plain weave fabric. The effective elastic constants of fabric composite were calculated using meso-mechanics theory. A progressive failure analysis was performed using ABAQUS software to obtain the ultimate strength and failure mode of the sample. In addition, the damage process, failure mode and damage position was further studied. The bending properties of the joints were also presented by quasi-static load test using a three-point bending test device. Results of the ultimate load and damage analyses are compared to experimental data. The accuracy of the method was proved by the consistency of the relation between the load displacement curve trend and the correlation of the damage position and failure pattern.

The Effect of Fiber Content on the Crashworthiness Parameters of Natural Kenaf Fiber-Reinforced Hexagonal Composite Tubes

2016 ◽  
Vol 11 (1) ◽  
pp. 155892501601100
Author(s):  
M. F. M. Alkbir ◽  
S. M. Sapuan ◽  
A. A. Nuraini ◽  
M. R. Ishak
Keyword(s):  
Failure Mode ◽  
Transverse Crack ◽  
Failure Modes ◽  
Progressive Failure ◽  
Fiber Content ◽  
Fiber Reinforced ◽  
Kenaf Fiber ◽  
Buckling Failure ◽  
The Mean ◽  
Woven Kenaf

The aim of this paper is to study the effect of fiber content on the crashworthiness parameters (i.e., energy absorption and stroke efficiency) and the failure modes of a non-woven kenaf (mat) fiber-reinforced hexagonal composite tube. The composite was prepared and fabricated using the hand-lay-up method; fabrication was followed by axial compression testing using an Instron 3382 machine. Various fiber contents were considered, including 25%, 30%, 35% and 40%. A fiber content of 25% to 30% (mass percent) resulted in the best crashworthiness parameters. Furthermore, the amount of energy absorbed decreased as the fiber content increased, as did the mean crash load and the stroke efficiency. A few distinct failure modes were identified during the experiments, including the progressive failure mode, in which failure begins at the top end of the tube, and the transverse crack failure mode, which is associated with the buckling failure mode; after the crash occurs, the top or bottom end of the hexagonal tube begins to break and is fragmented into small pieces.

The failure mechanism of carbon fiber-reinforced composites under longitudinal compression considering the interface

2017 ◽  
Vol 24 (3) ◽  
pp. 429-437 ◽  
Author(s):  
Geng Han ◽  
Zhidong Guan ◽  
Xing Li ◽  
Ruipeng Ji ◽  
Shanyi Du
Keyword(s):  
Failure Mechanism ◽  
Failure Mode ◽  
Cohesive Zone Model ◽  
Progressive Failure ◽  
Micromechanical Model ◽  
Kink Band ◽  
Zone Model ◽  
Longitudinal Compression ◽  
Fiber Failure ◽  
Damage Initiation

AbstractIn this paper, a longitudinal compression experiment of composites was conducted and the macroscopic failure mode was obtained. Also, the microscopic failure morphologies of longitudinal compression and kink band were observed by using scanning electron microscopy. It can be seen that, under compression, fibers bend and form a kink band, which is the most typical failure mode. Then a micromechanical model of fiber random distribution based on the random collision algorithm, which can reveal the progressive failure mechanism of longitudinal compression considering the kink-band deformation, was established, with two dominant damage mechanisms – plastic deformation and ductile damage initiation of the polymer matrix and interfacial debonding included in the simulation by the extended Drucker-Prager model and cohesive zone model, respectively. Through numerical simulation, the loading and failure procedures were divided into three stages: elastic domain, softening domain and fiber failure domain. It can be concluded that the kink band was a result of fiber instability (micro-bulking), which is caused by the elastic bending of fibers. The fibers rotate and break into two places, forming a kink band. Then the fibers rotate further until the matrix between the fibers fails and the kink-band breaks and, hence, the composite loses its load-bearing capability.

Energy Absorption Mechanism of Thermoplastic Fiber-Reinforced Plastics under Impact Loading Using Split-Hopkinson Pressure-Bar Method

2020 ◽  
Vol 858 ◽  
pp. 47-52
Author(s):  
Ayuta Nambu ◽  
Shogo Adachi ◽  
Tomoya Yabu ◽  
Yuji Ishitsuka ◽  
Atushi Hosoi ◽  
...  
Keyword(s):  
Failure Mode ◽  
Split Hopkinson Pressure Bar ◽  
Progressive Failure ◽  
Mode Analysis ◽  
Fiber Reinforced ◽  
Hopkinson Pressure Bar ◽  
Impact Compression ◽  
Split Hopkinson ◽  
Energy Absorbing ◽  
Pressure Bar

The energy absorbing performance in the progressive failure of glass long-fiber-reinforced polyamide was evaluated by using the split Hopkinson pressure-bar method. An impact compression test of glass long-fiber-reinforced polyamide was performed from –30 °C to 90 °C, and the temperature-independent energy absorbing performance was confirmed only for the progressive failure mode. To clarify this phenomenon, compression tests, interlaminar compressive shear tests and mode-I fracture-toughness tests were conducted under static and impact conditions. The compression strength and the shear strength of all specimens decreased with an increase in temperature. The toughness improved with temperature. In addition to the mechanical tests, failure-mode analysis was performed by using a three-dimensional X-ray microscope to clarify the absorbing mechanism. From the above, it was concluded that the temperature-independent energy absorbing performance results from a balance of these mechanical properties against the temperature change.

scholarly journals Effect of Defects on Progressive Failure Behavior of Plain Weave Textile Composites

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4363
Author(s):  
Kyeongsik Woo ◽  
Jae Hyuk Lim ◽  
Cheolheui Han
Keyword(s):  
Failure Mode ◽  
Composite Structures ◽  
Progressive Failure ◽  
Tensile Load ◽  
Textile Composites ◽  
Unit Cell ◽  
Structural Safety ◽  
Uniaxial Tensile ◽  
Failure Behavior ◽  
Plain Weave

Various types of internal defects occur during manufacturing and handling of composite materials. It is practically impossible to manufacture composite structures without defects, making it crucial to understand the effect of defects on their failure behavior to maintain structural safety. In this work, the effect of pre-defects on the failure behavior of plain weave textile composites was studied. Unit cell configurations with symmetric, in-phase, and shifted fiber tow arrangements were considered. Inter-laced warp and fill tows and matrix pockets of plain weave unit cells were modeled in three-dimensional finite elements, and cohesive elements were inserted between all bulk elements to account for the fracture modes of the fiber and matrix direction failure of warp and fill tows, matrix pocket failure, and interface failure. Unit cell models containing pre-defects of voids, tow-matrix pocket separation, warp-fill tow separation, and cracks in the warp and fill tows were analyzed, and their effects on progressive failure behavior were investigated in terms of the interaction between fiber tow arrangements and defects. Results indicated that initial failure occurred in matrix-direction failure mode in fill tows, whereas fiber tow-matrix pocket separation was the major failure mode under uniaxial tensile load. Furthermore, failure behavior was found to be highly dependent on the fiber tow arrangement pattern and the location of pre-defects.

Numerical modeling of progressive failure of rigid piles under embankment load

2019 ◽  
Vol 56 (1) ◽  
pp. 23-34 ◽  
Author(s):  
Gang Zheng ◽  
Xinyu Yang ◽  
Haizuo Zhou ◽  
Jinchun Chai
Keyword(s):  
Tensile Stress ◽  
Failure Mode ◽  
Shear Failure ◽  
Slip Surface ◽  
Progressive Failure ◽  
Soft Clay ◽  
Bending Moment ◽  
Tensile Failure ◽  
Failure Behavior ◽  
Embankment Load

Rigid piles (e.g., concrete piles) have been widely used to improve soft clay for the rapid construction of embankments. In this study, a damage plasticity model that considers the brittle failure behavior of concrete and the frictional properties along cracks is proposed to study the progressive failure of rigid piles under an embankment load. The mechanical characteristics of piles in different locations have been analyzed. The results show that the essential failure mode for rigid piles is tensile failure, which is primarily governed by the distribution of the bending moment and the axial force within the piles. Pile rupture releases stress and causes a significant increase in the tensile stress within neighboring piles, possibly leading to the progressive failure of adjacent piles. Failure in the upper section of piles ultimately leads to the propagation of a slip surface and the global failure of the embankment. The parametric analysis indicates that increases in the pile stiffness and the embankment load result in a higher tensile stress within the piles and a change in the failure mechanism from shear failure to bending failure. In addition, a failure envelope is proposed to determine the failure mode of the piles.

Analytical electron microscopy of grain boundaries in Al-Cu metallizations

1992 ◽  
Vol 50 (2) ◽  
pp. 1684-1685
Author(s):  
J. R. Michael ◽  
A. D. Romig ◽  
D. R. Frear
Keyword(s):  
Electron Microscopy ◽  
Integrated Circuits ◽  
Failure Mode ◽  
Current Density ◽  
Thermal History ◽  
Analytical Electron Microscopy ◽  
Cu Metallization ◽  
Analytical Electron ◽  
Interconnect Lines

Al with additions of Cu is commonly used as the conductor metallizations for integrated circuits, the Cu being added since it improves resistance to electromigration failure. As linewidths decrease to submicrometer dimensions, the current density carried by the interconnect increases dramatically and the probability of electromigration failure increases. To increase the robustness of the interconnect lines to this failure mode, an understanding of the mechanism by which Cu improves resistance to electromigration is needed. A number of theories have been proposed to account for role of Cu on electromigration behavior and many of the theories are dependent of the elemental Cu distribution in the interconnect line. However, there is an incomplete understanding of the distribution of Cu within the Al interconnect as a function of thermal history. In order to understand the role of Cu in reducing electromigration failures better, it is important to characterize the Cu distribution within the microstructure of the Al-Cu metallization.

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