Soft Failure Research Articles

Biomechanical Comparison of Transosseous Knotless Rotator Cuff Repair Versus Transosseous Equivalent Repair: Half The Anchors With Equivalent Biomechanics?

To compare the biomechanics of a transosseous equivalent (TOE) repair using medial and lateral anchors with tape to a transosseous knotless (TOK) tape repair with only laterally placed intraosseous anchors. One of 2 different repairs were performed on 8 paired specimens: (1) transosseous equivalent (TOE) tape repair or (2) transosseous knotless (TOK) tape repair. Specimens were mounted on a materials testing machine and loaded in uniaxial tension to measure cyclic construct gap formation, followed by failure testing. Paired t tests were used to compare gapping, ultimate stiffness, and failure loads. Fisher exact test was used to compare modes of failure (soft tissue failure vs construct failure). Peak cyclic gapping, failure stiffness, and ultimate failure loads did not differ between TOE and TOK repairs (P= .140 for gapping, P= .106 for stiffness, and P= .672 for peak failure loads). All TOK repairs failed via soft tissue failure medial to the medial suture line, with no construct failures. TOE repairs failed more often through construct failure (anchor migration or suture-bone interface cut through) than TOK repairs (P= .026). TOK repairs only failed through soft tissue whereas TOE repairs failed through both soft tissue and the repair construct. Despite 50% fewer suture anchors in the TOK repairs than the TOE repairs, cyclic gapping and ultimate stiffness and failure loads were not significantly different. The transosseous knotless construct presented is a 2-anchor construct that is equivalent in biomechanical function to a traditional 4-anchor construct, reducing anchor load in the tuberosity.

Perspective approach in using anti-oxidation and anti-wear particles from oil to estimate residual technical life of a system

Abstract Indirect diagnostic measures have big potential for estimating a system condition. One of these are oil data. Since the oil is in direct contact with the observed system, oil data are of great importance and value. Usually the authors analyse its physio-chemical properties, or the concentration of selected wear particles. In our article, however, we take into account a completely novel attitude towards anti-oxidation and anti-wear particles (AOWP). Their great importance lies in the fact that the AOWP concentration depends on both an operation time and a calendar time. Due to the extensive oil field data the dependence on an operation time and a calendar time is available. The development of the AOWP particles concentration is modelled stochastically with the use of the Wiener process with drift, or generally with a diffusion process. The aim is to set the trajectory of oil or engine degradation, and set the probability of an engine soft failure. In order to compare our results obtained by using the diffusion process of Wiener type we apply the Fuzzy Inference System (FIS). The results are expected to help us to estimate the residual technical life of a system, optimize the maintenance and make life cycle costs more effective. The system is meant to be the oil itself and the combustion engine where the oil is used.

Contribution of Technical and Human Factors to “No Fault Found” Events

Multicomponent products that combine hardware and software (cars, airplanes, and telephones, to name a few) are everywhere in our lives. The commercial release of such products is a compromise between performance capabilities, competitive pricing, and time to market (Challa, Rundle, & Pecht, 2013). As product performance increases, system complexity and the number of failure modes also increase. Of particular importance are “No Fault Found” (NFF) events that occur when a user records a system error and subsequent investigations fail to uncover the reason for the system malfunction – the root cause is unknown (Jones & Hayes, 2001). NFF can result in high warranty costs, product recalls, and diminished reputation (Challa et al., 2013). Surprisingly, most organizations do not explicitly calculate the costs of NFF or use a framework to estimate them (Erkoyuncu, Khan, Hussain, & Roy, 2016). A defining aspect of NFF is the discrepancy between actual and anticipated use conditions (Challa et al., 2013). Anticipated use is often defined by qualification, the passing of tests that demonstrate when a product meets nominal design and manufacturing specifications (Challa et al., 2013). A popular form of qualification is standards-based testing due to its speed, low cost, and applicability to many products (Challa et al., 2013). Standards such as Military Standard (MIL-STD) meet these criteria, but are often inappropriate for specific, actual-use conditions in the field. For example, the Ford Motor Company designed thick film integrated (TFI) ignition modules based on a set of laboratory standards. Cars used in hot climates experienced numerous failures that were initially classified as NFF (because these failures could not be reproduced under the milder laboratory conditions) (Thomas et al., 2002). One remedy to this problem would be to adopt more stringent engineering specifications for qualification. In this research, we analyzed NFF across four industries – automotive electronics, aerospace, medical equipment, and consumer electronics. The analysis is based on four contributors to NFF: testing procedures, intermittent failures, environmental factors, and human factors. Intermittent failures are the re-appearance of equipment failure after remedial actions have taken place (Thomas et al., 2002). Environmental factors (also referred to as environmental monitoring) are the context (or “background”) conditions in which the NFF event occurs. These factors can take on a variety of forms, from vibration and humidity in an aircraft to the diverse demographics of users of a consumer electronic product (Kim & Christiaans, 2016; Moffat, Abraham, Desmulliez, Koltsov, & Richardson, 2008). Case studies (representing each of the four industries) demonstrate that the existing strategies for reducing the occurrence of NFF events are limited. Addressing the four contributors to NFF (testing procedures, intermittent failures, environmental factors, and human factors) allows for the development of a systematic approach to reduce these events. First, one must distinguish between “hard” and “soft” failures. Hard failures are technical or equipment reliability failures (den Ouden, Yuan, Sonnemans, & Brombacher, 2006; Kushniruk & Patel, 2004). Soft failures occur when products fail to meet usability expectations, despite functioning from a technical, reliability standpoint (den Ouden et al., 2006). Hard failures are relevant to the aerospace and automotive electronics industry case studies, while soft failures pertain to medical equipment and consumer electronics. Analysis reveals a number of key insights, including the impact of proper failure classification (what is or is not a NFF event). Proper classification enables organizations to quantify how products perform in the field and which corrective actions are needed to improve reliability and usability.

11.16: Seismic performance evaluation of MRFS with dissipative continuous columns

ABSTRACTThe Dissipative Continuous Column (DCC) concept is proposed as a gravity load and seismic energy dissipating dual‐functional structural component. The proposed DCC is made up of two closely spaced continuous columns which are interconnected with replaceable steel strip dampers (RSSDs) over the height. It works in a way similar to pin supported coupled shear walls, but minimizes the construction invasive and ensure rapid return to occupancy after severe earthquakes. The innovative moment resisting frame (MRF) system with DCCs can also mitigate the inter‐storey drift concentration and reduce the soft storey failure risk significantly due to the contribution of large flexure stiffness of the DCCs. Based on the experimental test results, a simplified analysis model of the DCCs is developed for the design and seismic performance evaluation of the MRFs system with DCCs. The simplified analysis model consists of dual column and multiple zerolength equivalent elasto‐plastic springs with rigid end. Numerical models of a 4‐story conventional steel MRF and a 4‐story steel MRF with DCCs were set up using the proposed simplified model. Nonlinear Dynamic Time History Analysis were undertaken, and the results showed that the MRFs with DCCs can reduce the economic loss by limiting the structural damage in the replaceable steel strip dampers and mitigating both the maximum inter‐story drift ratio and drift concentrations.

Optimal maintenance policy considering maintenance errors for systems operating under performance-based contracts

In recent years, performance-based contracts (PBCs) have been extensively adopted in both manufacturing and service industries. However, maintenance strategies under PBCs are not often addressed. This paper considers a novel maintenance policy for a single-component system operating under a PBC. Failures of this system may either be hard or soft, but can only be revealed by periodic inspection. Imperfect repair (subject to the virtual age model) is used to fix a soft failure. However, imperfect repair actions may be ineffective and could cause a catastrophic failure (maintenance error) that ultimately leads to replacement. In the model proposed in this paper, we consider maintenance error, and the system is replaced upon a hard failure, a maintenance error, or preventively replaced at the nth soft failure. The objective of this model is to maximize the expected net revenue of the supplier operating under a PBC. Moreover, we compare the properties of the optimal maintenance policy under three different failure rate functions and show that, with different parameters, our model reduces to several classic maintenance models. Finally, a case study on a wind turbine system is provided to illustrate the application of the maintenance model.

A cohesive damage-plasticity model for DEM and its application for numerical investigation of soft rock fracture properties

The failure of soft rocks is highly concerned in both research and practice due to the vulnerability of materials and its involvement in a wide range of foundation and mine collapses. Different methods have been suggested to study the fracture characteristics of soft rocks. In this study, a discrete-based modelling method is proposed, as an alternative to existing continuum methods, to analyse the fracturing behaviour of soft rocks. A new cohesive model coupling damage mechanics with plasticity theory is formulated to characterise the failure mechanisms of cement bridges between aggregates in the materials. In conjunction with the discrete element method (DEM), the proposed modelling method can produce realistic modelling of soft rock failure, demonstrated through good agreements between experimental and numerical results in both specimen responses and crack patterns. Based on this, further analyses of soft rock failure are carried out, focusing on the influence of specimen geometries on the material fracture toughness measured in a semi-circular bending test. The simulation results agree well with their experimental counterparts while being less scattered than the experimental data. This demonstrates the effectiveness of the proposed method in characterising fracture properties of soft rocks and opens more potentials for a better understanding of soft rock failure.

The seismic reliability of two connected SMRF structures

This article aims to investigate the possible retrofitting of a deficient building with soft story failure mode by connecting it to an adjacent building which is designed based on current code with friction dampers at all floors. Low cost and high performance reliability along with significant energy dissipation pertaining to stable hysteretic loops may be considered in order to choose the proper damper for connecting adjacent buildings. After connecting two neighbouring floors by friction dampers, the sliding forces of dampers at various stories are set in two arrangements: uniform sliding force and then variable sliding force. In order to account for the stochastic nature of the seismic events, incremental dynamic analyses are employed prior and after the installation of the friction dampers at the various floors. Based on these results, fragility curves and mean annual rate of exceedance of serviceability and ultimate limit states are obtained. The results of this study show that the collapse mode of the deficient building can affect the optimum arrangement of sliding forces of friction dampers at Collapse Prevention (CP) performance level. In particular, the Immediate Occupancy (IO) performance level is not tangible to the sliding force arrangement and it depends solely on sliding force value. Generally it can be claimed that this rehabilitation scheme can turn the challenge of pounding two adjacent buildings into the opportunity of dissipating a large amount of the seismic input energy by the friction dampers, thus improving significantly the poor seismic performance of the deficient structure.

Advances in rocking core-moment frame analysis

The paper introduces a number of new analytic techniques and practical technologies that lead to the development of an efficient earthquake resistant system. The proposed structural system consists of a grade beam supported moment frame connected to a rigid rocking core through story level rigid links. The new system tends to bend and tilt as an upright simply supported beam with minimal uniform drift and prevents the formation of soft story failure within the moment frame. It is capable of preventing severe damage to its columns and footings and can be equipped to prevent catastrophic collapse due to strong ground motion and re-center itself afterwards. The analytic development is based on global, design led analysis and results in closed form, exact solutions that are highly suitable for preliminary, manual, as well as spread sheet computations. Several examples have been provided to verify and demonstrate the applications of the proposed formulations. All numerical results have been verified by independent computer analysis.

Prediction of LIN communication robustness against EFT events using dedicated failure models

During its life, an automotive application can encounter several perturbations such as fast transient of ESD discharges. In this paper, we propose a LIN transceiver behavior model to predict both hard and soft failures within a communication link. The proposed model, extracted from measurements, is implemented into simulation as a failure block. We will show that depending on the output state of the LIN, the data reading behavior could be different. Using such model, corrections at system level can be implemented to avoid failures.

Extra-articular shoulder resections: outcomes of 54 patients

The survival of patients with tumors around the shoulder treated with extra-articular resection, the rates of reconstructions-related complications, and the function of the shoulder cannot be estimated because of limited available data from mainly small published related series and case reports. We studied 54 patients with tumors around the shoulder treated with extra-articular shoulder resections and proximal humeral megaprosthetic reconstructions from 1985 to 2012. Mean tumor volume was 549 cm3, and the mean length of the proximal humeral resection was 110 mm. Mean follow-up was 7.8 years (range, 3-21 years). We evaluated the outcomes (survival, metastases, recurrences, and function) and the survival and complications of the reconstruction. Survival of patients with malignant tumors was 47%, 38%, and 35%, at 5, 10, and 20 years, respectively. Rates for metastasis and local recurrence were 60% and 18.5%, respectively. Survival was significantly higher for patients without metastases at diagnosis, tumor volume <549 cm3, and type IV resections. Survival of reconstructions was 56% at 10 years and 48% 20 years. Overall, 19 patients (35.2%) experienced 30 complications (55.5%), the most common being soft tissue failures that required subsequent surgery without, however, implant removal. The mean Musculoskeletal Tumour Society score was 25 points, without any significant difference between the types of extra-articular resections. Tumor stage and volume as well as type of resection are important predictors of survival of patients with malignant tumors around the shoulder. Survival of the reconstructions is satisfactory; nevertheless, the complication rate is high. The Musculoskeletal Tumour Society score is similar with respect to the type of resection.

АНАЛИЗ ПОКАЗАТЕЛЕЙ НАДЕЖНОСТИ И СЛОЖНОСТИ РЕАЛИЗАЦИИ РАЗЛИЧНЫХ ВАРИАНТОВ СТРУКТУР АВТОМАТА С ПАМЯТЬЮ ПРИ ПОТОКЕ МЯГКИХ ОТКАЗОВ

АНАЛИЗ ПОКАЗАТЕЛЕЙ НАДЕЖНОСТИ И СЛОЖНОСТИ РЕАЛИЗАЦИИ РАЗЛИЧНЫХ ВАРИАНТОВ СТРУКТУР АВТОМАТА С ПАМЯТЬЮ ПРИ ПОТОКЕ МЯГКИХ ОТКАЗОВ

Reliability modeling for mutually dependent competing failure processes due to degradation and random shocks

• Reliability model for mutually dependent competing failure processes is proposed. • Soft, hard failures and their interaction are depicted by Stress–Strength model. • Hard failure threshold level is positively correlated on degradation performance. • Numerical double integration is adopted to compute the proposed reliability model. • Example analysis shows the mutual dependence has important effect on reliability. Many systems are subject to two mutually dependent competing risks namely degradation and random shocks, and they can fail due to two competing modes of failure, soft and hard failure. Soft failure occurs when the total degradation performance, including continuous degradation and sudden degradation increments caused by random shocks, exceeds a certain critical threshold level. Hard failure occurs when the magnitude of any shock (extreme shock model) or the accumulated damage of shocks (cumulative shock model) is beyond some strength threshold level, which is affected by the temporal degradation performance. From viewpoints of Stress-Strength models and Cumulative damage/shock model, a realistic reliability model is developed in this article for mutually dependent competing failure processes due to degradation and random shocks. Finally, a numerical example of Micro-Electro-Mechanical System (MEMS) is conducted to illustrate the implementation and effectiveness of the proposed model.

Comparison of Tunnel and Crestal Incision Techniques in Reconstruction of Localized Alveolar Defects.

The aim of this study was to compare the complication rates of recipient sites prepared using two incision techniques: crestal and tunnel. In this prospective study, patients underwent augmentation procedures (68 patients; 75 sites) by the same surgeon that were performed consecutively using the crestal incision technique (27 horizontal, 10 vertical; crestal group) or the tunnel incision technique (27 horizontal, 11 vertical; tunnel group). Autogenous bone block grafts were harvested with a piezoelectric surgical device, and the grafts were fixed at the recipient sites by two titanium screws in both groups. The authors evaluated minor exposure, transient paresthesia, major exposure, permanent paresthesia, gingival recession at adjacent teeth, surgery time, and visual analog scale pain scores. Soft tissue dehiscence and graft failure were significantly lower in patients undergoing the tunnel technique. The tunnel incision technique significantly decreased soft tissue exposure, the most common complication of augmentation procedures with autogenous onlay bone grafts. This technique should be considered an alternative to the crestal incision technique for preparation of the recipient site.

Impacts of Leakage-Biasing Failure-Mode Identification in the Transmission-Line Pulse Testing for Low-/High-Voltage MOSFET Components

The effects of leakage-biased voltage ( V LB) levels are investigated in this paper, which are set for failure-mode identification on the final fault diagnostic measurement in transmission line pulse (TLP) testing. To identify the effect on electrostatic discharge (ESD) robustness, three types of MOSFET components were employed; namely, low-voltage n -channel MOSFET (LVnMOS) (5 V/0.6 μm), high-voltage n-channel MOSFET (HVnMOS), and high-voltage p-channel MOSFET (HVpMOS) (12 V/1.8 μm) devices under test (DUTs), respectively. After a series of systematic TLP measurements, this study determined that the set VLB level substantially influenced the failure mode identification and I t2 value decision on the LVnMOS and HVnMOS DUTs, but its effect on the HVpMOS DUT was extremely weak. According to the secondary breakdown current ( I t2) values, the error caused by a maximum V LB level was up to 55.6% in the LVnMOS DUT, 81% in the HVnMOS DUT, and only 3.38% in the HVpMOS DUT. Consequently, this engendered a considerable deviation in most data derived from testing DUTs through TLP compared with those derived from a human-body model (HBM). Hence, to ensure a high correlation between values measured through TLP testing NNand an HBM for the same DUTs, the V LB level should be considered during TLP testing. The lack of correlation is demonstrated to be due to a moderate soft and hard failure during TLP measurement especially for the LVnMOS and HVnMOS samples. Therefore, to obtain accurate I t2 values for DUTs, the V LB level for the failure-mode identification in TLP testing should be within a low-biasing range (such as kept V LB ≤ 5 V).

Modelling of degradation and a soft failure moment during the operation of a supercapacitor applying selected diffusion processes

Abstract An important requirement imposed on storage batteries nowadays is to have sufficient capacity. At the same time a high level of availability, reliability and safety is required as well. Our intention is to determine a capacity degradation threshold and the moment the soft failure of a graphite supercapacitor (SC) occurs. If we do not take into account the idle state, the functioning of the supercapacitor might be expressed by charging and discharging processes under different operating conditions given by the allowed extent of SC design. When looking for the degradation threshold and the moment of soft failure occurrence we performed the experimental part of measuring in the climatic chamber. We performed and recorded the processes of SC charges and discharges at different temperatures: 40 °C, 25 °C and −42 °C and at different charging and discharging currents: 2A, 4A, 6A and 8A. The experimental results were used to model mathematically the SC discharge process. Appropriate tools used for SC discharge are diffusion processes. In this case we apply a Wiener process with drift and an Ito process.

Contribution to prediction of soft and hard failure occurrence in combustion engine using oil tribo data

Abstract When assessing technical systems, we apply different condition indicators. If we take into account indirect diagnostic indicators, lubricant seems to be a very good source of different information. Where the oil is part of a system, it is possible to get the information about the oil condition as well as the system itself. In this article we focus on the system of piston combustion engine and tribodiagnostic data. The indirect diagnostic information is the concentration level of contaminating particles in the oil. We observe specific particles of oil contamination - soot which is formed in the operation as a by-product during fuel combustion. The soot contaminates the oil significantly and the soot concentration shows under what conditions the system was operated. It also indicates that the system condition gradually deteriorates. We have a statistically very interesting set of data from the operation of heavy off-road vehicles. The recorded soot operation data depend on a few operation values: kilometres [km], days [day] and moto-hours [Mh]. Modelling a soft and a hard failure which might occur the moment the concentration reaches its critical value is performed with selected stochastic diffusion processes, namely the Wiener process with drift and the Ornstein-Uhlnbeck process. The main aim and contribution of our article is to estimate and study the distribution of the first hitting time of a critical threshold and to determine the moment when the soft and hard failure occurs in a vehicle. We also try to estimate the engine useful residual life. We are aware, however, that there are numerous possibilities of using these results.

Modeling of interior beam-column joints for nonlinear analysis of reinforced concrete frames

Beam-column connections undergo significant shear deformations and greatly contribute to story drifts during earthquake loading, yet their response is typically neglected in traditional frame analyses through the use of rigid end offsets. Although local joint models are available in the literature for the investigation of single, isolated joints, there is a lack of holistic frame analysis procedures simulating the joint behavior in addition to important global failure modes such as beam shear, column shear, column compression, and soft story failures. The objective of this study is to capture the impact of local joint deformations on the global frame response in a holistic analysis by implementing a joint model into a previously-developed global frame analysis procedure. The implemented joint element simulates the joint shear deformations and bar-slip effects. Concrete confinement effects are also considered so that both older and modern joints can be modeled. The developed procedure successfully captures the local load-deflection response of joints within a global frame analysis procedure. The ratio of predicted and observed peak load had a mean of 1.25 before the modification, and a mean of 1.05 after the modification.

Research and application on the horizontal tectonic stress influence on the stability of deep roadway

According to the test result of ground stress of -817.0m Horizontal shaft station in Huainan mine area, the stress field distribution characteristic of mainly with horizontal tectonic stress was analyzed, the deep roadway surrounding rock deformation and failure regularity under the situation of the maximum horizontal stress and roadway axis in the different angle were studied by using the FLAC3D simulation software, and then specific way of supporting and its parameters were designed combined with the shaft station layout conditions. The result shows that: the roadway stability is relatively good when its tunnel axis the maximum horizontal stress direction within 30° angle, surrounding rock deformation and the plastic zone at the top and bottom are significantly increasing along with the angle increased from 30° to 90°, the major form of deep soft rock deformation and failure is the floor heave. According to the simulation results, the conditions under the layout condition of the shaft station roadway, support methods and support parameters have been designed and determined. The supporting method can be referenced by the similar mines.

In-depth circuits edit analysis to reveal the implantation-related defect

IC functional failure is always a challenge for failure analysis engineers since it needs test pattern to access the defect location and electrically trigger it. Dynamic failure analysis is the only way to be used to do this kind of analysis. But it's time consuming and complex to employ dynamic analysis, so the success rate is lower and cycle time is longer. Static failure analysis is impossible to apply on these kinds of analysis since the test pattern and design information is needed. However, in this paper, the application of advanced FIB circuit edit (CE) was employed to isolate the suspected function block, and make it accessible to the DC bias. With static FA analysis, the defect location was successfully localized. Nanoprobing was employed on the further electrical analysis, and abnormal electrical performance was successfully observed. Combined with the device physics analysis, the suspected process was identified. Further PFA Wright etch was applied to visualize the defect which was a soft failure of Bipolar Junction Transistor (BJT) device. Failure mechanism was built up to explain the electrical and physical phenomena successfully.

Optimal multi-level condition-based maintenance policy for multi-unit systems under economic dependence

The study aims to work on multi -level condition-based maintenance (CBM) policy for multi-unit systems under economic dependence. Failure modes of units are classified as hard failure or soft failure and taken into account in this paper. Unlike previous works which only considered setup cost dependence with a single failure mode, two types of economic dependence are considered, which are setup cost-saving, and additional cost and time that can be saved when identical maintenance tasks and expertise are needed. In this study, hard failure provides an opportunity for additional inspection and repair of soft-type units, and soft failure creates an opportunity for replacement of the hard-type unit as its age exceeds opportunistic threshold. They both undergo preventive maintenance (PM) when the level/age exceeds preventive threshold at inspection epochs. The objective of this study is to determine the optimal opportunistic control limit and preventive control limit for each unit such that the system’s average long-run maintenance cost per unit time is minimized. The optimization problem is formulated in a semi-Markov decision process (SMDP) framework. The explicit formula for the mean residual life is derived for the proposed model which enables the estimation of the remaining useful life and allows maintenance engineers to plan maintenance early based on the observed information. Finally, the method is illustrated by an industrial case study of a feed system of a machine tool. A comparison with other methods is given, which illustrates the effectiveness of our approach.