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Circuits may fail in the field due to a wide variety of failure modes. If there are frequent failures in the field, circuits are returned to the manufacturer, and the causes of failure must be identified. The challenge is that wearout mechanisms are confounded in circuit and system-level failure data. Using such failure data, it is often hard to separate the underlying failure causes without time-consuming and expensive physical failure analysis. To distinguish the wearout mechanisms for each failure sample, we have developed a quick and low-cost methodology using maximum likelihood estimation and probability analysis to determine the origin of the failure distributions, region of error, and sorting accuracy. We apply our methodology to analyze the competing wearout mechanisms in 14nm FinFET ring oscillators, as an example, using simulation. We also consider the problem of Trojan detection.
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Dynamic Localized Failure of Soils via Nonlocal Poromechanics Model: A Case Study of the Lower San Fernando Dam Failure
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This paper discusses three points inspired by Skraaning and Jamieson’s perspective on automation failure: (a) the limitations of the automation failure concept with expanding system boundaries; (b) parallels between the failure to grasp automation failure and the failure to grasp trust in automation; (c) benefits of taking a pluralistic approach to definitions in sociotechnical systems science. While a taxonomy of automation-involved failures may not directly improve our understanding of how to prevent those failures, it could be instrumental for identifying hazards during test and evaluation of operational systems.more » « less
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null (Ed.)Hydrogels have gained recent attention for biomedical applications because of their large water content, which imparts biocompatibility. However, their mechanical properties can be limiting. There has been significant recent interest in the strength and fracture toughness of hydrogel materials in addition to their stiffness and time-dependent behavior. Hydrogels can fail in a brittle manner, although they are extremely compliant. In this work, the failure and fracture of hydrogels are examined using a compression test of spherical hydrogel particles. Spheres of commercially available polyacrylamide–potassium polyacrylate were hydrated and tested to failure in compression as a function of loading rate. The spheres exhibited little relaxation when compressed to small fixed displacements. The distributions of strength values obtained were examined in a particle fracture framework previously used for brittle ceramics. There was loading rate dependence apparent in the measured peak force and calculated peak strength values, but the data fell on a single empirical distribution function of strength for the hydrogels regardless of loading rate. Strength values for these hydrogels were mostly in the range of 0.05–0.3 MPa, illustrating the challenges using hydrogels for mechanically demanding applications such as tissue engineering.more » « less
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1061/9780784483701.002
