Early Failure Mode Research Articles

Mechanical Behavior of Waste Tire Steel Fiber–Modified Mine-Cemented Backfilling Materials: Early Strength, Toughness, and Failure Mode

Mechanical Behavior of Waste Tire Steel Fiber–Modified Mine-Cemented Backfilling Materials: Early Strength, Toughness, and Failure Mode

Deep Drawing Behaviour of Steel–Glass Fibre-Reinforced and Non-Reinforced Polyamide–Steel Sandwich Materials

Thermoplastic-based fibre metal laminates (FMLs) have gained increasing interest in the automotive industry due to their forming potential—especially at higher temperatures—into complex components compared to thermoset-based ones. However, several challenges arise while processing thermoplastic-based FMLs. One the one hand, forming at room temperature (RT) leads to early failure modes, e.g., fracture and delamination. On the other hand, warm forming can extend their forming limits, although further defects arise, such as severe thickness irregularities and wrinkling problems. Therefore, this study focuses on developing different approaches for deep drawing conditions to deliver a promising, feasible, and cost-effective method for deep-drawn FML parts. We also describe the defects experimentally and numerically via the finite element method (FEM). The FMLs based on steel/glass fibre-reinforced polyamide 6 (GF-PA6/steel) are studied under different deep drawing conditions (temperatures, punch, and die dimensions). In addition, mono-materials and sandwich materials without fibre reinforcement are investigated as benchmarks. The results showed that the best deep drawing condition was at a temperature of 200 °C and a die/punch radius ratio of 0.67, with a gap/thickness ratio of ≤2.0. The FEM simulation via Abaqus 6.14 was able to successfully replicate the anisotropic properties and wrinkling of the GF-PA6 core in an FML, resembling the experimental results.

Early life failure modes and downtime analysis of onshore type-III wind turbines in Turkey

Operations and maintenance costs, and unplanned downtime accounts for a significant proportion of the total expenditure of windfarms. Therefore, reduction of these costs is essential, which requires a better understanding of the wind turbines' reliability in terms of failure rates and downtime with operational lifetime. Failure rates and downtime are generally logged using condition monitoring systems, which mainly focus on Supervisory Control and Data Acquisition (SCADA) alarm signals. The aim of this paper is to use SCADA alarm statistics to provide a new failure rate and downtime survey and thus to evaluate reliability performance of the major wind turbine components and subsystems. The paper focuses on a modern onshore windfarm located in Turkey with Type-III wind turbines over the course of the first two years of operations, which is the first time reliability data from Turkey has been published in literature.

Connection between micron-sized defects and dielectric strength of poly(dimethylsiloxane) elastomer films

The quality of dielectric elastomer (DE) films is a key factor affecting the reliability of DE actuators. Reported here is the effect of the number of micron-sized defects on dielectric strength (DS) for poly(dimethylsiloxane) (PDMS) DE films. Using the same PDMS formulation but different procedures, we produced two model DE films with a thickness of approximately 50 μm. The two PDMS DE films suitably serve as a good-quality model film (EF1) and a low-quality model film (EF2) for this study, as shown by a large difference in the number of micron-sized defects found using micro-Raman techniques. The internal defects with various micron sizes in the two PDMS DE films can be quantitatively analyzed using an optical flaw inspection technique. According to two-parameter Weibull analysis, our assumption is that EF2 has a bimodal distribution of breakdown field (Eb) consisting of failure mode 1 in the early failure range and failure mode 2 in the late failure range. The values of the electric field (E) at the failure probability of 63.2%, defined as the scale parameter and regarded as DS, are 76.3 V μm−1 for EF1, and 39.1 and 69.6 V μm−1 for EF2, respectively. For the Eb distribution, the shape parameters estimated are 18.3 for EF1, and 4.7 and 10.2 for EF2, respectively. The results support the idea that there are different failure mechanisms between EF1 and EF2. The difference in the total number of internal defects, 12 for EF1 and 92 for EF2 per area of approximately 15 mm × 15 mm, should explain such a large variation in DS and Eb distribution. Our findings show the beneficial use of the quantitative analytical approach for micron-sized defects associated with the quality control and premature breakdown of DE films.

Physics-Based Machine Learning: Data Needs and Practices for Failure Mode Classification and Life Prediction

Machine learning and other advanced analysis approaches hold promise to reduce the time and effort needed to transition a new battery technology from innovation to deployment. Prediction of life and performance from sparse data is a key part of the technology revolution which will serve as a cornerstone of a reduced carbon energy future. Complimenting the prediction of life is the classification and prediction of specific failure modes and mechanisms to provide sufficient feed back to the R&D process so that key technology gaps can be addressed earlier and to ensure appropriate measures are taken to reduce long-term development costs.Here we discuss the use of machine learning to perform early failure mode classification and life prediction. Looking at two distinct sets of data for different fast charging applications provides the opportunity to extend differing levels of physicality to predictions. In the first instance a set of Nissan Leaf cells are used for prediction of performance to less than 1.2% mean absolute percent error.1 In the second instance a combination of experimental and synthetic data are used for failure mode classification and quantification for research cells used for extreme fast charging.2 The comparison of one set of data using commercial cells and one using research cells provides opportunity to revisit key data acquisition parameters and best practices that will enhance future efforts.[1] M. Ross Kunz, Eric J. Dufek, Zonggen Yi, et al “Early battery performance prediction for mixed use charging profiles using hierarchal machine learning” Batter. Supercaps, 2021,DOI: 10.1002/batt.202100079[2] B.R. Chen, M.R. Kunz, T.R. Tanim, E.J. Dufek “A machine learning framework for early detection of lithium plating combining multiple physics-based electrochemical signatures” Cell Reports Physical Science, 2021, 2(3), 100352

Early failure mechanism research of electromechanical product based on meta-action

Early failure is the key factor that restricts the improvement of electromechanical product reliability. The research on early failure mechanism of electromechanical product can provide a basis for the subsequent failure cause tracing and failure diagnosis. At present, there are few systematic studies on the early failure mechanism of electromechanical product, which have the following shortcomings: firstly, the failure analysis objects in traditional failure methods cannot reflect the characteristic of electromechanical product that “motion determination electromechanical product function”; secondly, traditional failure analysis methods ignore the fact that mechanical and electronic systems are different in failure cause, failure mode and failure mechanism; thirdly, failure cause and failure mode are easily confused in traditional methods; finally, most of the traditional methods are qualitative analysis, which cannot directly show the generation process of failure. To address those problems, meta-action and meta-action unit of electromechanical product are selected as the analysis object herein. Early failure mode, early failure cause, and early failure mechanism of electromechanical product are defined and analyzed. A meta-action early failure mechanism quantitative analysis model considering electromechanical coupling is built, and the influence of failure cause on failure mode is analyzed. A CNC (computer numerical control) machine tool made in China is taken as an example. The results verify the applicability and correctness of the proposed method.

Why do knees after total knee arthroplasty fail in different parts of the world?

ObjectiveThe aim of this narrative review was to provide an overview of failure modes after total knee arthroplasty in different parts of the world based on data from worldwide representative studies and National Joint Registries. MethodsA review of the available literature was performed using the keyword terms “total knee arthroplasty”, “revision”, “failure”, “reasons”, “causes”, “complications”, “epidemiology”, “etiology”; “assessment”, “painful knee”, “registry” and “national” in several combinations. The following databases were assessed: Pubmed (https://pubmed.ncbi.nlm.nih.gov), Cochrane Reviews (https://www.cochrane.org), Google Scholar (https://scholar.google.com). In addition, registry data were obtained directly from national registry archives. Due to the heterogeneity of available data it was decided to present the review in a narrative manner. ResultsCurrent literature report that infection has become the primary acute cause of TKA failure, while aseptic loosening and instability remain the overall most frequent reasons for revisions. Based on national registries certain tendencies can be deducted. The predominant overall failure mode of aseptic loosening is particularly found in Japan, United Kingdom, New Zealand and Switzerland. Leading early TKA failure mode represents infection with percentages of 20–30% in Sweden, Australia, New Zealand, Japan and the United States. Higher numbers could only be found in clinical studies on the Asian continent such as Korea (38%), China (53%), Iran (44%) and India (87%). ConclusionAlthough there are regional differences in TKA failure modes, TKA fails worldwide especially due to infections and aseptic loosening. It is important to diagnose these in good time and reliably using appropriate, standardized diagnostics in order to recommend the best possible therapy to the patient.

Reliability based hardware Trojan design using physics-based electromigration models

In recent years the concern over Hardware Trojans has come to the forefront of hardware security research as these types of attacks pose a real and dangerous threat to both commercial and mission-critical systems. One interesting threat model utilizes semiconductor physics, specifically aging effects such as Electromigration (EM). However, existing methods for EM-based Trojans rely on empirical Black's models can easily lead to performance degradation and less accuracy in Trojan activation time prediction. In this article, we study the EM-based Trojan attacks based on recently developed physics-based EM models. We propose novel EM attack techniques in which the EM-induced hydrostatic stress increase in a wire is caused by wire structure or layer changes without changing the current density of the wires. The proposed techniques consist of sink/reservoir insertion or sizing and layer switching techniques based on the early and late failure modes of EM wear-out effects. As a result, the proposed techniques can have minimal impact on circuit performance, which is in contrast with existing current-density-based EM attacks. The proposed techniques can serve as a trigger for the EM attack on power/ground networks and signal and clock networks. Furthermore, we also present two potential EM attack mitigation techniques, namely, the split fabrication and burn-in testing.

Analysis of insulation resistance degradation in Ni–BaTiO3 multilayer ceramic capacitors under highly accelerated life test

The degradation mechanism of electrical breakdown in Ni–BaTiO3 multilayer ceramic capacitors (MLCCs) was studied by visualizing degraded areas in early failure and wear-out failure modes. The visualization was achieved by the fabrication of electrically degraded MLCCs just before electrical breakdown and by detection of the degraded area by infrared-optical-beam-induced resistance change (IR-OBIRCH) analysis. In the case of our prototype MLCCs, a thinner dielectric layer caused early failure and microstructural abnormalities in the dielectric layer caused wear-out failure. Such a visualization method directly demonstrates the causes of electrical breakdown in MLCCs.

Metallization Reliability and Defectivity in Compound Semiconductors

Compound semiconductor devices are in mass volume production yet our understanding of reliability and defectivity of III-V materials is still evolving. Process-induced defects in electroplated Au interconnect metallization on GaAs devices were detected during the course of reliability testing. Abnormally high lognormal sigmas (σ > 0.7) indicated the existence of a bi-modal failure mechanism. A distinct early lifetime failure mode was observed along with the intrinsic electromigration metallization wear-out failure mode. Increased temperature stress showed only a slight acceleration on the early failure mechanism but selection of a higher resistance degradation failure percentage criterion reduced the extent of these early failures. Physical characterization of the electroplated Au film revealed as-deposited nanoscale voids. Elimination of these voids through process improvement as well as suggested mechanisms for the early failures is discussed.

Metallization Reliability and Defectivity in Compound Semiconductors

Compound semiconductor devices are in mass volume production, yet our understanding of reliability and defectivity of III-V materials is still evolving. Process-induced defects in electroplated Au interconnect metallization on GaAs devices were detected during the course of reliability testing. Abnormally high lognormal sigmas (σ > 0.7) indicated the existence of a bi-modal failure mechanism. A distinct early lifetime failure mode was observed along with the intrinsic electromigration metallization wear-out failure mode. Failure analysis of an early Au structure failure showed an unusually large void at the atypical anode end. Physical characterization of the electroplated Au film revealed as-deposited nanoscale voids. Elimination of these voids through process improvement as well as proposed mechanisms for the early Au failures are discussed.

Reliability Detection of Process-Induced Metallization Defects in GaAs Devices

ABSTRACTProcess-induced defects in electroplated Au interconnect metallization on GaAs devices were detected during the course of reliability testing. Abnormally high lognormal sigma values (σ > 0.7) indicated the existence of a bi-modal failure mechanism. A distinct early lifetime failure mode was observed along with the intrinsic electromigration metallization wear-out failure mode. Physical characterization of the electroplated Au film revealed as-deposited nanoscale voids. Elimination of these voids through process improvement as well as suggested mechanisms for the early failures are discussed.

Highly reliable molecular-pore-stacking (MPS)/Cu interconnects featuring best combination of post-etching treatment and resputtering processes

Effects of post-etching treatment (PET) in trench patterning and resputtering in barrier metal sputtering on low-k/Cu interconnects were investigated for the low-k of molecular pore stacking (MPS). Optimized combination of PET and resputtering reduces wiring capacitance by 5% due to well controlled profile, resulted from hardening effect of the exposed MPS at the trench bottom. The developed process sequence achieves 10 times longer EM lifetime and eliminates early failure mode in the TDDB test. Thus, the novel process, featuring PET and resputtering, contributes to high reliability for 28nm node CMOS and beyond.

Medial Mobile Bearing Unicompartmental Knee Arthroplasty

Unicompartmental knee arthroplasty (UKA) is a less invasive treatment for medial gonarthrosis. However, registry data have demonstrated higher revision and early failure rates. The purpose of this study is to report the early survivorship and failure modes in a series of 1000 consecutive medial mobile bearing UKA. UKA patients with a minimum of 2 year follow-up or those meeting the study endpoint (UKA failure or death) were included. Demographic variables, pre and post-operative clinical variables, and mode of failure were analyzed. Eight hundred and thirty-nine knees were included in the analysis. Forty revisions were performed at an average of 23.1 months (range, 2.3-74.2) following UKA for a survivorship of 95.2%. Indications for revision were aseptic loosening (15), tibial collapse (7), mobile bearing dislocation (2), persistent pain (12), progression of disease (2), infection (1), and tibiofemoral instability (1). These results are from a single center and may not be comparable to those of larger reports such as national registries.

Early Failure Mode Effect and Criticality Analysis for CNC Machining Tools

According to the plentiful early failure data collected on the spots of 30 CNC machining tools with ATC (Automatic Tool Changer), FMECA method is used to analyze the main fault mode and facts which usually make a great possible impact on the reliability of these products during early failure period.We find out the fault positions and the ratios of the fault modes and fault causes. We further analyze the fault modes and fault causes which frequently arise in the subsystems and parts. Through the analyses of FMECA, we learn the weak links of CNC machining tools and provide bases for removing the products faults. Suggestions how to enhance reliability level of these products are proposed.

Improving Proximal Fixation and Seal with the HeliFx Aortic EndoAnchor

Endovascular aneurysm repair (EVAR) transformed the therapy for aortic aneurysms and introduced an era of widespread use for endovascular procedures in a variety of vascular beds. Although dramatic improvements in acute outcomes drove the early enthusiasm for EVAR, a realization that the long-term integrity of the endoprostheses used for EVAR were sometimes inferior to the results obtained with open surgical reconstruction dampened enthusiasm for their use in low-risk and younger patients who mandated long-term follow-up. While early EVAR failure modes are often related to technical aspects of the implantation, late failures are often related to the implant migrating from its original longitudinal position or losing wall apposition in the face of continued aneurysmal dilatation. Migration, or the failure of longitudinal fixation, results in gradual loss of aortic approximation and the eventual repressurization of the aneurysm sac with its attendant risks of growth and rupture. The inability of stent- and barb-based endovascular fixation to resist aortic dilatation at the site of fixation also represents a late failure mode that can result in aneurysm rupture. A variety of endostaples or endoanchors designed to replicate the function of an interrupted aortic suture have been proposed and tested to varying degrees over the years. The device designed and produced by Aptus EndoSystems, now called the HeliFx Aortic EndoAnchor is the only independent endovascular fixation device that has achieved significant clinical usage and Food and Drug Administration approval. The experience with this device is now more than 5 years and it is approved for use in the broad market across both Europe and the United States. This article will review the engineering and design concepts underlying the HeliFx device as well as the in vitro and in vivo results using this device. Finally, a discussion of the potential for technical, procedural, and endograft innovation based on the availability of endovascular suturing will be reviewed.

HAZOP Analysis of Product Requirements for Early Failure Mode Identification

AbstractSafety risk assessment begins with hazard identification, followed by elicitation of causes that could result in those hazards. Cause identification early in the design phase is function‐based by necessity, since components and sub‐systems are not fully defined. These system functions are defined by the product requirements. Applying HAZOP guideword analysis to product requirements can provide a list of initial hazard causes and functional failure modes of the system. This method provides early insight into safety risk controls that should be planned for and implemented early in the product design, when cost and schedule impacts are lowest.

Thermal stability of SiC Schottky diode anode and cathode metalisations after 1000 h at 350 °C

The thermal stability of two commercially available silicon carbide Schottky diode types has been evaluated following a 1000 h non-biased storage test under vacuum at 350 °C. The Ti-based Schottky (Anode) contact shows excellent stability over the duration of the test with less than 5% change in either extracted Schottky barrier height or ideality values. The Al die attach metalisation on the anode also shows no evidence of degradation after the test. However, a considerable change in series resistance was observed for both diode types, with up to a factor of 100 measured for one of the diodes. The primary early failure mode is related to degradation of the NiAg Ohmic (cathode) die attach metalisation. Demixing of the NiAg alloy, leading to Ag agglomeration is proposed to be the underlying degradation mechanism involved resulting in delamination of the die attach metalisation and the corresponding series resistance increase.

Large-scale statistical analysis of early failures in Cu electromigration, Part I: Dominating mechanisms

With continuing scaling of Cu-based metallization, the electromigration (EM) failure risk has remained one of the most important reliability concerns for advanced process technologies. The main factors requiring attention are the activation energy related to the dominating diffusion mechanism, the current exponent as well as the median lifetimes and lognormal standard deviation values of experimentally acquired failure time distributions. In general, the origin and scaling behavior of these parameters are relatively well understood. However, the observation of strong bimodality for the electron up-flow direction in dual-inlaid Cu interconnects has added complexity. The failure voids can occur both within the via (“early” mode) or within the trench (“late” mode). Over the last few years, bimodality has been reported also in down-flow EM, leading to very short lifetimes due to small, slit-shaped voids under vias. These voids, requiring only a very limited amount of mass movement, are generally causing concerns with respect to long-term, reliable chip operation at elevated temperatures. For a more thorough investigation of the aforementioned early failure phenomena, specific test structures were designed based on the Wheatstone Bridge (WSB) technique. The use of these structures enabled an increase in the tested sample size past 800 000 for the 90 nm technology node, allowing a direct analysis of EM failure mechanisms at the single-digit ppm regime. Results indicate that down-flow EM can exhibit bimodality at very small percentage levels, not readily identifiable with standard testing methods. The activation energy for the down-flow early failure mechanism was determined to be 0.83±0.01 eV. Within the small error bounds of this large-scale statistical experiment, this value is deemed to be significantly lower than the usually reported activation energy of 0.90 eV for EM-induced diffusion along Cu/SiCN interfaces. Due to the advantages of the WSB technique, we were also able to expand the experimental temperature range down to 150 °C, coming quite close to typical operating conditions up to 125 °C. As a result of the lowered activation energy, we conclude that the down-flow early failure mode may control the chip lifetime at operating conditions. This publication contains the first part of our large-scale statistical analysis of early failures in Cu EM. In the second part of this study, we will discuss the EM scaling behavior across 90, 65, and 45 nm technologies. In addition, short-length effects will be evaluated using our large-scale, statistical approach. Utilizing the advantages of the WSB technique, the total sample size will be increased past 1.2 million.

Effect of Zn doping on SnAg solder microstructure and electromigration stability

A comprehensive study on the effect of Zn-doped SnAg solders on microstructure and electromigration (EM) is reported. Minor Zn doping, about 0.6 wt %, in a SnAg solder alloy is found to be effective in stabilizing solder microstructure and improving EM reliability. Early EM failure modes in Zn-doped solders are significantly suppressed, resulting in a longer EM lifetime with tight distributions. Analyses using optical microscopy, scanning electron microcopy, transmission electron microscopy, electron microprobe analysis, and electron backscattering diffraction were conducted. Zn addition in SnAg leads to significant changes in solder microstructure, grain structure, and thermal and EM stabilities. The strong reaction of Zn with Cu atoms effectively slowed down the Cu diffusion in β-Sn grains, thus improved the EM stability of Sn-rich solder joints.