Failure modes and failure mechanisms of RC members strengthened by NSM CFRP composites – Analysis of pull-out failure mode

2012 ◽  
Vol 43 (4) ◽  
pp. 1893-1901 ◽  
Author(s):  
Firas Al-Mahmoud ◽  
Arnaud Castel ◽  
Raoul François
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Failure Mechanisms ◽  
Pull Out ◽  
Cfrp Composites

Methodology for Analysis of Schottky Diode Failures

2010 ◽  
Author(s):  
Bhanu P. Sood ◽  
Michael Pecht ◽  
John Miker ◽  
Tom Wanek
Keyword(s):  
Failure Mode ◽  
Schottky Diode ◽  
Failure Modes ◽  
Schottky Diodes ◽  
Failure Mechanisms ◽  
Forward Voltage ◽  
Fast Switching ◽  
Voltage Drops ◽  
The Common

Abstract Schottky diodes are semiconductor switching devices with low forward voltage drops and very fast switching speeds. This paper provides an overview of the common failure modes in Schottky diodes and corresponding failure mechanisms associated with each failure mode. Results of material level evaluation on diodes and packages as well as manufacturing and assembly processes are analyzed to identify a set of possible failure sites with associated failure modes, mechanisms, and causes. A case study is then presented to illustrate the application of a systematic FMMEA methodology to the analysis of a specific failure in a Schottky diode package.

scholarly journals Fatigue Behaviors of Resistance Spot Welds for 980 MPa Grade TRIP Steel

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1086
Author(s):  
Heewon Cho ◽  
Sangwoo Nam ◽  
Insung Hwang ◽  
Je Hoon Oh ◽  
Munjin Kang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Failure Mode ◽  
Trip Steel ◽  
Failure Modes ◽  
Propagation Speed ◽  
Outer Edge ◽  
Fatigue Load ◽  
Resistance Spot ◽  
Fracture Surfaces ◽  
Pull Out

The fatigue life of the resistance spot weld of 980 MPa grade transformation induced plasticity (TRIP) steel was investigated and failure modes and fracture surfaces according to the fatigue load were analyzed. The fatigue life according to the nugget size was observed by using two electrodes with face diameters of 8 mm and 10 mm. When an electrode face diameter with 10 mm was used, the nugget size was large, and the fatigue life was further increased. After the fatigue test, three types of failure modes were observed, namely pull-out, plug, and heat affected zone (HAZ) failure, depending on the fatigue load. The fracture surfaces in each failure mode were analyzed. In all failure modes, a crack was initiated in the HAZ region, which is the interface between the two materials in all failure modes. In the case of pull-out failure, the crack propagates as if it surrounds the nugget at the outer edge of the nugget. In the case of HAZ failure, the crack propagates in the thickness direction of the material and outward in the nugget shell. Plug failure occurs with pull-out failure and HAZ failure mixed. The propagation patterns of cracks were different for each failure mode. The reason why the failure mode and the fracture surface are different according to the fatigue load is that the propagation speed of the fatigue crack is fast when the fatigue load is relatively large and is slow when the fatigue load is low.

Design and Simulation of a Microcontroller Based Loudspeaker Protection System Against Amplifier Direct Current (D.C) Offsets

2016 ◽  
Vol 8 ◽  
pp. 12
Author(s):  
Abiodun Ogunseye ◽  
Olamide Omolara Olusanya
Keyword(s):  
Failure Mode ◽  
Power Amplifier ◽  
Direct Current ◽  
Failure Modes ◽  
Failure Mechanisms ◽  
Protection System ◽  
Amplifier Circuit ◽  
Switching Transistor ◽  
Detection Circuit ◽  
Critical Components

A number of failure mechanisms can result in the damage of loudspeakers that are directly connected to an audio power amplifier system. One of such failure modes occurs when the amplifier circuit develops an output d.c voltage, in which case, the loudspeaker coil will be damaged by overheating. D.c offset detection circuits, usually based on simple transistor circuits are normally used to protect the loudspeaker against this failure mode. However, as effective as they are, these circuits can fail in ways that can result in loudspeaker damage. In this work, a microcontroller based circuit that monitors the critical components of a loudspeaker d.c detection circuit, namely the switching transistor and the isolating relay circuit was developed. The hardware of the developed circuit was modelled with Proteus® software and its firmware was written using MikroC® software. The modelled circuit successfully detects the presence of d.c signals and also reports the states of the isolating relay and the switching transistors when these components fail.

Experimental researches on failure and energy absorption of composite laminated thin-walled structures

2020 ◽  
Vol 54 (27) ◽  
pp. 4253-4268
Author(s):  
Mou Haolei ◽  
Xie Jiang ◽  
Zou Jun ◽  
Feng Zhenyu
Keyword(s):  
Energy Absorption ◽  
Failure Mode ◽  
Specific Energy ◽  
Failure Modes ◽  
Circular Tube ◽  
Failure Mechanisms ◽  
Specific Energy Absorption ◽  
Thin Walled Structures ◽  
Crushing Force ◽  
Thin Walled

To research the failure of carbon fiber-reinforced composite laminated specimens, the tensile tests and compressive tests were conducted for [90]16 and [0]16 specimens, and the shear tests were conducted for [±45]4s specimens, and the microscopic failure mechanisms were observed by scanning electron microscopy. To research the failure and energy absorption of different thin-walled structures with different layups, the quasi-static axial crushing tests were conducted for [±45/0/0/90/0]s and [0/90]3s circular tubes, [0/90]3s and [±45]3s square tubes, [0/90]4s and [±45]4s sinusoidal specimens, and the internal failure were further investigated by 3D X-ray scan. Based on the load-displacement curves, the energy absorptions were evaluated and compared according to specific energy absorption and peak crushing force, and the relationships between failure modes and specific energy absorption, peak crushing force were further researched. The results show that the macroscopic failure modes are the collective results of varieties of microscopic failure mechanisms, such as fiber fracture, matrix deformation and cracking, interlamination and intralamination cracks, cracks propagation, etc. The [±45/0/0/90/0]s circular tube shows the transverse shearing failure mode with high specific energy absorption. The [±45]3s square tube and [±45]3s sinusoidal specimen show the local buckling failure mode with low specific energy absorption. The [0/90]4s sinusoidal specimen, [0/90]3s circular tube, and [0/90]3s square tube show the lamina bending failure mode with medium specific energy absorption. The failure mode of thin-walled structure can be changed by reasonable layups design, and the energy absorption can further be improved.

scholarly journals Influence of Bond Behaviour of Flexural GFRP Reinforcement on Failure Mechanisms in Beams Without Stirrups

2018 ◽  
Vol 64 (4) ◽  
pp. 269-283
Author(s):  
M. Kaszubska ◽  
R. Kotynia
Keyword(s):  
Shear Strength ◽  
Failure Mode ◽  
Failure Modes ◽  
Shear Failure ◽  
Shear Crack ◽  
Failure Mechanisms ◽  
Crack Pattern ◽  
Critical Crack ◽  
Bond Behaviour ◽  
Gfrp Bars

AbstractThe aim of the paper is to investigate the shear failure mechanisms in T-shape, single span and simply supported beams exclusively reinforced with longitudinal glass fiber reinforced polymer (GFRP) bars. Usually the critical shear crack in RC beams without stirrups develops through the theoretical compression strut reducing the shear strength following the shear failure. The main parameter affecting the crack pattern and the shear strength of the beams is the shear slenderness. However, the test results presented in the paper indicated the new arching effect due to the bond losing between the GFRP flexural reinforcement and concrete. This failure mode revealed unexpected critical crack pattern and failure mode. The research of concrete beams flexurally reinforced with GFRP bars without stirrups indicated two failure modes: typical shear-compression and a new one leading by the bond losing between the ordinary reinforcement and concrete.

scholarly journals Effects of 1-Ethyl-3-(3-Dimethylaminopropyl) Carbodiimide on Adhesion of Posts in Teeth Obturated With Different Sealers

2020 ◽  
Vol 31 (4) ◽  
pp. 417-422
Author(s):  
Beatriz Serrato Coelho ◽  
Flávia Sens Fagundes Tomazinho ◽  
Denise Piotto Leonardi ◽  
Fabrício Scaini ◽  
Marilisa Carneiro Leão Gabardo ◽  
...  
Keyword(s):  
Bond Strength ◽  
Failure Mode ◽  
Failure Modes ◽  
Resin Cement ◽  
Root Canals ◽  
Pull Out ◽  
Significant Difference ◽  
Ah Plus ◽  
Failure Mode Classification ◽  
Endodontic Sealers

Abstract The aim of this study was to evaluate the effect of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) on bond strength of fiberglass posts in root canals obturated with different endodontic sealers. Seventy-eight mandibular premolars were obturated with three sealers (n=26): Endofill (END), AH Plus (AHP), and Endosequence BC Sealer (EBS). After preparation of the post space, two subgroups were formed according to the cementation of the posts (n=13): with EDC (EDC), and without EDC (control - CON). The specimens were submitted to a pull-out test, failure mode classification, and root canal surface evaluation by scanning electron microscopy after post displacement. Regarding the bond strength, a significant difference between the EDC and CON subgroups occurred only in the END (p=0.001). No difference was detected among the CON subgroups (p=0.339). However, among the EDC subgroups, AHP presented significantly higher values (END versus AHP: p=0.001; AHP versus EBS: p=0.016). Upon classification of failure modes, score 1 (≥ 50% of cement) was the most commonly observed, except for the END + EDC. Remains of endodontic sealers and resin cements were found in the cervical third, but without statistical difference (p=0.269), while in the middle third, difference occurred (p=0.004). In conclusion, EDC decreases bond strength when associated with END sealer, without changing the failure mode between the resin cement and fiberglass post. The best performance was observed when EDC was combined with AHP sealer.

Combine Nanoprobing Technique with Difference Analysis to Identify Nonvisual Failures

2006 ◽  
Author(s):  
Cha-Ming Shen ◽  
Tsan-Cheng Chuang ◽  
Jie-Fei Chang ◽  
Jin-Hong Chou
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Electrical Characteristic ◽  
The Novel ◽  
Difference Analysis ◽  
Original Idea ◽  
Deductive Method ◽  
Complete Measurement

Abstract This paper presents a novel deductive methodology, which is accomplished by applying difference analysis to nano-probing technique. In order to prove the novel methodology, the specimens with 90nm process and soft failures were chosen for the experiment. The objective is to overcome the difficulty in detecting non-visual, erratic, and complex failure modes. And the original idea of this deductive method is based on the complete measurement of electrical characteristic by nano-probing and difference analysis. The capability to distinguish erratic and invisible defect was proven, even when the compound and complicated failure mode resulted in a puzzling characteristic.

Case Study and Fault Modeling for Wrong Redundancy Evaluation on DRAM Devices

2007 ◽  
Author(s):  
Martin Versen ◽  
Dorina Diaconescu ◽  
Jerome Touzel
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Fault Modeling ◽  
Mode Analysis ◽  
Root Cause ◽  
Failure Mode Analysis

Abstract The characterization of failure modes of DRAM is often straight forward if array related hard failures with specific addresses for localization are concerned. The paper presents a case study of a bitline oriented failure mode connected to a redundancy evaluation in the DRAM periphery. The failure mode analysis and fault modeling focus both on the root-cause and on the test aspects of the problem.

scholarly journals Microstructure and Mechanical Performance of Resistance Spot Welded Martensitic Advanced High Strength Steel

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1021
Author(s):  
Yunzhao Li ◽  
Huaping Tang ◽  
Ruilin Lai
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Strong Dependence ◽  
High Strength ◽  
Weld Nugget ◽  
Resistance Spot ◽  
Pull Out ◽  
Cross Tension ◽  
Spot Welded

Resistance spot welded 1.2 mm (t)-thick 1400 MPa martensitic steel (MS1400) samples are fabricated and their microstructure, mechanical properties are investigated thoroughly. The mechanical performance and failure modes exhibit a strong dependence on weld-nugget size. The pull-out failure mode for MS1400 steel resistance spot welds does not follow the conventional weld-nugget size recommendation criteria of 4t0.5. Significant softening was observed due to dual phase microstructure of ferrite and martensite in the inter-critical heat affected zone (HAZ) and tempered martensite (TM) structure in sub-critical HAZ. However, the upper-critical HAZ exhibits obvious higher hardness than the nugget zone (NZ). In addition, the mechanical properties show that the cross-tension strength (CTS) is about one quarter of the tension-shear strength (TSS) of MS1400 weld joints, whilst the absorbed energy of cross-tension and tension-shear are almost identical.

Failure mode and effect analysis (FMEA) to improve collaborative project-based learning: Case study of a Study and Research Path in mechanical engineering

2021 ◽  
pp. 030641902199904
Author(s):  
Elena Bartolomé ◽  
Paula Benítez
Keyword(s):  
Active Learning ◽  
Failure Mode ◽  
Mechanical Engineering ◽  
Failure Modes ◽  
Collaborative Study ◽  
Project Based Learning ◽  
Educational Process ◽  
Effect Analysis ◽  
Questions And Answers

Failure Mode and Effect Analysis (FMEA) is a powerful quality tool, widely used in industry, for the identification of failure modes, their effects and causes. In this work, we investigated the utility of FMEA in the education field to improve active learning processes. In our case study, the FMEA principles were adapted to assess the risk of failures in a Mechanical Engineering course on “Theory of Machines and Mechanisms” conducted through a project-based, collaborative “Study and Research Path (SRP)” methodology. The SRP is an active learning instruction format which is initiated by a generating question that leads to a sequence of derived questions and answers, and combines moments of study and inquiry. By applying the FMEA, the teaching team was able to identify the most critical failures of the process, and implement corrective actions to improve the SRP in the subsequent year. Thus, our work shows that FMEA represents a simple tool of risk assesment which can serve to identify criticality in educational process, and improve the quality of active learning.

Sign in / Sign up

Export Citation Format

Share Document