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Fundamentals of Probabilistic Aerospace Electronics Reliability Engineering
Published in Ephraim Suhir, Human-in-the-Loop, 2018
The bathtub curve, the experimental “reliability passport” of a mass-fabricated product, reflects the inputs of two critical irreversible processes—the statistics-of-failure process that results in a reduced failure rate with time (this is particularly evident from the infant mortality portion of the curve) and the physics-of-failure (aging, degradation) process that leads to an increased failure rate with time (this trend is explicitly exhibited by the wear out portion of the bathtub diagram). Could these two critical processed be separated [6]? The need for that is due to the obvious incentive to minimize the role and the rate of aging, and this incentive is especially significant for products like lasers, solder joint interconnections, and others, which are characterized by long wear out portions and when it is economically infeasible to restrict the product’s lifetime to the steady-state situation, when the two irreversible processes in question compensate each other to a greater or lesser extent.
Design for Six Sigma
Published in Suresh Patel, The Tactical Guide to SIX SIGMA Implementation, 2017
The model used to describe failure patterns of a product population over the entire life of the product is called the bathtub curve, named for its shape (Figure 9.5). The bathtub curve is a “plot” of failure rate versus time. It shows how fast product failures are taking place, and if the failure rate is increasing, decreasing, or staying the same. The curve is divided into three regions: Region where burn-in failures and infant mortality failures take placeRegion of stable operating lifeRegion of accelerated failure and wear-out failure
Component Reliability Analysis
Published in Mohammad Modarres, Mark P. Kaminskiy, Vasiliy Krivtsov, Reliability Engineering and Risk Analysis, 2016
Mohammad Modarres, Mark P. Kaminskiy, Vasiliy Krivtsov
The chance-failure region of the bathtub curve exhibits a reasonably constant failure rate, characterized by random failures of the component. In this period, many mechanisms of failure due to complex underlying physical, chemical, or nuclear phenomena give rise to this approximately constant failure rate. The third region, called the wear out region, which exhibits an increasing failure rate (IFR), is characterized mainly by complex aging phenomena. Here, the component deteriorates (e.g., due to accumulated fatigue) and is more vulnerable to outside shocks. It is helpful to note that these three regions can be radically different for different types of components. Figures 3.2 and 3.3 show typical bathtub curves for mechanical and electrical devices, respectively.
Predictive maintenance: assessment of potentials for residential heating systems
Published in International Journal of Computer Integrated Manufacturing, 2023
The ‘bathtub curve‘ (Figure 3) indicates that a new system shows a high failure rate due to design, material, manufacturing, and installation errors during the first phase of operation. The decrease of the so-called early failures causes a decrease of the failure rate. This phase is followed by an operating time interval mainly characterized by random failures (Figure 3: Phase II). During this phase with a relatively constant failure rate, failures are mainly caused by external influences on the system. These include environmental stress, inadmissible loads, operating errors, but also inadequately executed maintenance measures. In the subsequent phase (Figure 3: Phase III), wear-related failures occur in addition to the randomly caused ones already described. These have their origin primarily in wear processes, e.g. due to deterioration, fatigue, or corrosion. The consequences of these wear processes are expressed in an increase of the failure rate (Schenk 2010).
Reliability Prediction Methods for Electronic Devices: A State-of-the-art Review
Published in IETE Technical Review, 2022
Vinay Kumar, Lalit Kumar Singh, Anil Kumar Tripathi
The failure rate represents the limit of the probability that a failure occurs per unit time interval, provided that no failure has taken place before time, . In other words, the failure rate is the frequency with which a system or component failure occurs. It is represented in failures per unit of time. Figure 1 demonstrates a failure rate curve as a function of time, also called the bathtub curve. Bathtub curve [6] is broken into three different regions in the reference of time, they are: The first region, where the failure rate decreases called infant mortality or early failure.The second region, where failure rate relatively constant called useful life, andThird and a final region, where failure rate increases called wear out or aging.
The additive Perks distribution and its applications in reliability analysis
Published in Quality Technology & Quantitative Management, 2022
Luis Carlos Méndez-González, Luis Alberto Rodríguez-Picón, Ivan Juan Carlos Pérez Olguín, Vicente García, David Luviano-Cruz
Reliability engineering has become a handy quality tool to determine the life behavior of any class of devices. One of the most widely used concepts in reliability is the description of device failures through the bathtub curve (see Figure 1). The concept of the bathtub curve lists that during the early stage of the device (infant mortality), failures can arise due to the manufacturing process or the quality of the components. The failures at this point behave in an exponentially decreasing way until stabilizing. When the device enters the stabilization stage, this is considered the operating use stage.