Failure Analsys of Wrapped Pin Joint of Composite and Metal

2012 ◽  
Vol 433-440 ◽  
pp. 514-519
Author(s):  
Jiang Sun ◽  
Blahouš Karel
Keyword(s):  
Failure Analysis ◽  
Failure Modes ◽  
Numerical Results ◽  
Filament Winding ◽  
Experimental Results ◽  
Tensile Failure ◽  
Composite Manufacturing

By filament winding technology, a pin hole can be formed in the process of composite manufacturing through wrapped fiber tow around pin, so fiber tows around the pin hole are continued. The paper presents the failure analysis for this kind of pin hole. The experimental results and numerical results show that the pin hole has a good tensile bearing ability. According to Hashin criteria, numerical results show that main failure modes are fiber tensile failure and matrix tensile failure which are agreed with the experimental results.

scholarly journals Numerical and Experimental Failure Analysis of Carbon Fiber-Reinforced Polymer-Based Pyrotechnic Separation Device

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Mingfa Ren ◽  
Fei Weng ◽  
Jing Sun ◽  
Zhifeng Zhang ◽  
Zhiguo Ma ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Failure Analysis ◽  
Failure Mode ◽  
Failure Modes ◽  
Lightweight Design ◽  
Shaped Charge ◽  
Tensile Failure ◽  
Fiber Reinforced ◽  
Metal Materials ◽  
Separation Devices

Current pyrotechnic separation devices are mainly made of metal materials, limiting the capacity of lightweight design in advanced launching vehicles. With the outstanding mechanical properties, such as high mass-specific strength and modulus, carbon fiber-reinforced polymers (CFRPs) have the potential to replace metal materials in pyrotechnic seperaton devices. However, to improve the seperation reliability of these pyrotechnic separation devices, there still needs further understanding on the the failure mode of CFRP composites under linear shaped charge (LSC). In this paper, cutting tests were carried out on CFRPs for the failure analysis of CFRPs under LSC, and nonlinear finite element analysis (FEA) was performed to characterize the evolution of LSC cutting in CFRPs. According to experimental simulation and numerical simulation, it can be found that the three main failure modes in CERPs while subjected to LSC jet are shear failure, delamination failure, and tensile failure. In the early cutting stage, the initial time of damage of the fiber and the matrix near the shaped charge shows less difference and the laminate is directly separated by the energy of high-speed jet. When the jet velocity decreases, the jet morphology collapses and matrix damages precede into the fiber, which would cause tensile failure mode of CFRPs. Meanwhile, the delamination in low jet speed stages is larger than that in the high jet speed stages. These studies on the failure modes of CFRPs under LSC provide important basis for the future design of CFRP-based pyrotechnic separation devices, which is important to the lightweight design of launching vehicles.

Deformation and Stress Analsys of Wrapped pin Joint between Composite and Metal

2012 ◽  
Vol 548 ◽  
pp. 393-397
Author(s):  
Jiang Sun ◽  
Qi Xiao
Keyword(s):  
Stress Analysis ◽  
Numerical Results ◽  
Filament Winding ◽  
Composite Manufacturing ◽  
Deformation Ability ◽  
Stress And Deformation

By filament winding technology, a pin hole can be formed in the process of composite manufacturing through wrapped fiber tow around pin, so fiber tows around the pin hole are continued. The paper presents the deformation and stress analysis for this kind of pin hole and compares those with ordinary pin hole. The numerical results show that the wrapped pin hole has a good stress and deformation ability.

Failure Analysis Case Study of a 1.5 Meter Space Flex Harness

2017 ◽  
Author(s):  
Erick Kim ◽  
Kamjou Mansour ◽  
Gil Garteiz ◽  
Javeck Verdugo ◽  
Ryan Ross ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Failure Modes ◽  
Field Of View ◽  
Area Of Interest ◽  
Air Stream ◽  
Novel Method ◽  
Temperature Controlled ◽  
Non Destructive ◽  
Failure Site

Abstract This paper presents the failure analysis on a 1.5m flex harness for a space flight instrument that exhibited two failure modes: global isolation resistances between all adjacent traces measured tens of milliohm and lower resistance on the order of 1 kiloohm was observed on several pins. It shows a novel method using a temperature controlled air stream while monitoring isolation resistance to identify a general area of interest of a low isolation resistance failure. The paper explains how isolation resistance measurements were taken and details the steps taken in both destructive and non-destructive analyses. In theory, infrared hotspot could have been completed along the length of the flex harness to locate the failure site. However, with a field of view of approximately 5 x 5 cm, this technique would have been time prohibitive.

Case Studies of Brittle Interfacial Failures in Area Array Solder Interconnects

2000 ◽  
Author(s):  
George M. Wenger ◽  
Richard J. Coyle ◽  
Patrick P. Solan ◽  
John K. Dorey ◽  
Courtney V. Dodd ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Case Studies ◽  
Failure Modes ◽  
Electroless Nickel ◽  
Electrical Performance ◽  
Printed Wiring Board ◽  
Solder Interconnects ◽  
Area Array ◽  
Surface Finishes ◽  
Soldering Reaction

Abstract A common pad finish on area array (BGA or CSP) packages and printed wiring board (PWB) substrates is Ni/Au, using either electrolytic or electroless deposition processes. Although both Ni/Au processes provide flat, solderable surface finishes, there are an increasing number of applications of the electroless nickel/immersion gold (ENi/IAu) surface finish in response to requirements for increased density and electrical performance. This increasing usage continues despite mounting evidence that Ni/Au causes or contributes to catastrophic, brittle, interfacial solder joint fractures. These brittle, interfacial fractures occur early in service or can be generated under a variety of laboratory testing conditions including thermal cycling (premature failures), isothermal aging (high temperature storage), and mechanical testing. There are major initiatives by electronics industry consortia as well as research by individual companies to eliminate these fracture phenomena. Despite these efforts, interfacial fractures associated with Ni/Au surface finishes continue to be reported and specific failure mechanisms and root cause of these failures remains under investigation. Failure analysis techniques and methodologies are crucial to advancing the understanding of these phenomena. In this study, the scope of the fracture problem is illustrated using three failure analysis case studies of brittle interfacial fractures in area array solder interconnects. Two distinct failure modes are associated with Ni/Au surface finishes. In both modes, the fracture surfaces appear to be relatively flat with little evidence of plastic deformation. Detailed metallography, scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and an understanding of the metallurgy of the soldering reaction are required to avoid misinterpreting the failure modes.

Failure Modes, Reliability Analysis and Case Studies on the Integration of Copper and Low-K Technology

2004 ◽  
Author(s):  
Huixian Wu ◽  
James Cargo ◽  
Huixian Wu ◽  
Marvin White
Keyword(s):  
Failure Analysis ◽  
Case Studies ◽  
Cross Section ◽  
Focused Ion Beam ◽  
Failure Modes ◽  
Ion Beam ◽  
Copper Interconnects ◽  
Wet Chemical ◽  
Low K ◽  
Section Analysis

Abstract The integration of copper interconnects and low-K dielectrics will present novel failure modes and reliability issues to failure analysts. This paper discusses failure modes related to Cu/low-K technology. Here, physical failure analysis (FA) techniques including deprocessing and cross-section analysis have been developed. The deprocessing techniques include wet chemical etching, reactive ion etching, chemical mechanical polishing and a combination of these techniques. Case studies on different failure modes related to Cu/low k technology are discussed: copper voiding, copper extrusion; electromigration stress failure; dielectric cracks; delamination-interface adhesion; and FA on circuit-under-pad. For the cross-section analysis of copper/low-K samples, focused ion beam techniques have been developed. Scanning electron microscopy, EDX, and TEM analytical analysis have been used for failure analysis for Cu/low-K technology. Various failure modes and reliability issues have also been addressed.

Failure Analysis Strategies for Multistacked Memory Devices with TSV Interconnects

2015 ◽  
Author(s):  
Frank Altmann ◽  
Christian Grosse ◽  
Falk Naumann ◽  
Jens Beyersdorfer ◽  
Tony Veches
Keyword(s):  
Failure Analysis ◽  
Focused Ion Beam ◽  
Failure Modes ◽  
Ion Beam ◽  
Memory Devices ◽  
Metallographic Cross Section ◽  
Electron Beam Induced Current ◽  
Thermal Simulations ◽  
Lock In ◽  
Non Destructive

Abstract In this paper we will demonstrate new approaches for failure analysis of memory devices with multiple stacked dies and TSV interconnects. Therefore, TSV specific failure modes are studied on daisy chain test samples. Two analysis flows for defect localization implementing Electron Beam Induced Current (EBAC) imaging and Lock-in-Thermography (LIT) as well as adapted Focused Ion Beam (FIB) preparation and defect characterization by electron microscopy will be discussed. The most challenging failure mode is an electrical short at the TSV sidewall isolation with sub-micrometer dimensions. It is shown that the leakage path to a certain TSV within the stack can firstly be located by applying LIT to a metallographic cross section and secondly pinpointing by FIB/SEM cross-sectioning. In order to evaluate the potential of non-destructive determination of the lateral defect position, as well as the defect depth from only one LIT measurement, 2D thermal simulations of TSV stacks with artificial leakages are performed calculating the phase shift values per die level.

scholarly journals Stress–strain relationship model of glulam bamboo under axial loading

2020 ◽  
Vol 29 ◽  
pp. 2633366X2095872
Author(s):  
Yang Wei ◽  
Mengqian Zhou ◽  
Kunpeng Zhao ◽  
Kang Zhao ◽  
Guofen Li
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Failure Modes ◽  
Axial Loading ◽  
Tensile Failure ◽  
Stress Strain ◽  
Laminated Bamboo ◽  
Bamboo Scrimber ◽  
Strain Relationship ◽  
Strain Model

Glulam bamboo has been preliminarily explored for use as a structural building material, and its stress–strain model under axial loading has a fundamental role in the analysis of bamboo components. To study the tension and compression behaviour of glulam bamboo, the bamboo scrimber and laminated bamboo as two kinds of typical glulam bamboo materials were tested under axial loading. Their mechanical behaviour and failure modes were investigated. The results showed that the bamboo scrimber and laminated bamboo have similar failure modes. For tensile failure, bamboo fibres were ruptured with sawtooth failure surfaces shown as brittle failure; for compression failure, the two modes of compression are buckling and compression shear failure. The stress–strain relationship curves of the bamboo scrimber and laminated bamboo are also similar. The tensile stress–strain curves showed a linear relationship, and the compressive stress–strain curves can be divided into three stages: elastic, elastoplastic and post-yield. Based on the test results, the stress–strain model was proposed for glulam bamboo, in which a linear equation was used to describe the tensile stress–strain relationship and the Richard–Abbott model was employed to model the compressive stress–strain relationship. A comparison with the experimental results shows that the predicted results are in good agreement with the experimental curves.

Simulation of a Free Standing Riser Model and Validation With Experimental Results

2014 ◽  
Author(s):  
Marcio Yamamoto ◽  
Sotaro Masanobu ◽  
Satoru Takano ◽  
Shigeo Kanada ◽  
Tomo Fujiwara ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Previous Experiment ◽  
Numerical Results ◽  
Experimental Results ◽  
Previous Article ◽  
Scale Model ◽  
Analysis Software ◽  
Free Standing ◽  
Reduced Scale

In this article, we present the numerical analysis of a Free Standing Riser. The numerical simulation was carried out using a commercial riser analysis software suit. The numerical model’s dimensions were the same of a 1/70 reduced scale model deployed in a previous experiment. The numerical results were compared with experimental results presented in a previous article [1]. Discussion about the model and limitations of the numerical analysis is included.

On the Stresses in a Notched Strip

1952 ◽  
Vol 19 (2) ◽  
pp. 141-146
Author(s):  
Chih-Bing Ling
Keyword(s):  
Infinite System ◽  
Linear Equations ◽  
Numerical Results ◽  
Theoretical Solution ◽  
Experimental Results ◽  
System Of Linear Equations ◽  
Transverse Bending ◽  
Longitudinal Tension

Abstract In a previous paper by the author (1), a theoretical solution for a notched strip under longitudinal tension is given. The result demands the solution of an infinite system of linear equations. A considerable amount of labor is involved in solving such a system. It seems, however, that the labor can be diminished by adapting to the solution a process known as the promotion of rank. In this paper such a process is described and then applied to solve the problem of a notched strip under transverse bending. The solution of this problem seems also to be new. The numerical results obtained are compared graphically with the experimental results available.

Investigation of the tensile performance and failure mechanism of carbon–aramid hybrid fibers/epoxy sandwich structure laminates using the UV-thermal synergetic curing mechanism: Experimentation and simulation

2018 ◽  
Vol 22 (8) ◽  
pp. 2582-2603
Author(s):  
Jiaojiao Xi ◽  
Xiaoyan Liu ◽  
Zhiqiang Yu
Keyword(s):  
Finite Element ◽  
Failure Mechanism ◽  
Sandwich Structure ◽  
Experimental Results ◽  
Tensile Failure ◽  
Hybrid Fibers ◽  
Pull Out ◽  
Tensile Performance ◽  
Hybrid Laminates ◽  
Curing Agents

The tensile failure mechanism of carbon–aramid hybrid fibers/epoxy sandwich structure laminates was investigated by using experimental and finite element methods. Double curing agents, triarylsulfonium hexafluoroantimonates and triethylene tetramine with a mass ratio of 4:15 were introduced into the laminates. Sandwich structure laminates, with different proportions of hybrid fibers, were cured by UV-initiated anion/cationic dual curing technique. The results showed that the synergetic curing effects of two curing agents were observed under UV irradiation, leading to the better curing of the system, which further plays a positive influence on the mechanical performance. The tensile properties and failure mechanism of the laminates depended on the stacking sequence and fiber volume fractions of the layer structures. The interplay hybrid laminates, containing three alternate plies with fiber contents of 67.7 vol%, presented the optimal tensile performance, and its tensile strength and modulus were 0.82 GPa and 22.09 GPa, respectively. The fracture morphologies revealed that pull-out and debonding of fibers were the main failure mechanism of hybrid laminates. The performance of sandwich structure laminates was determined by the load-carrying capacity of carbon fiber and load-transferring capacity of the aramid fiber and adhesive. The finite element model based on experiments was established to simulate the stress state and failure mechanism of sandwich laminates. The results demonstrated that the stress was better transferred into carbon fibers from the aramid fibers and adhesive, and the relative error rate of maximum stress from finite element analysis and experimental results was less than 5%, which were in reasonable agreement with the experimental results.

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