scholarly journals The propensity of the over-stressed rock masses to different failure mechanisms based on a hybrid probabilistic approach

2022 ◽  
Vol 119 ◽  
pp. 104214
Author(s):  
Roohollah Shirani Faradonbeh ◽  
Abbas Taheri ◽  
Murat Karakus
Keyword(s):  
Failure Mechanisms ◽  
Probabilistic Approach ◽  
Rock Masses

FDEM numerical modeling of failure mechanisms of anisotropic rock masses around deep tunnels

2021 ◽  
pp. 104535
Author(s):  
Penghai Deng ◽  
Quansheng Liu ◽  
Xing Huang ◽  
Yucong Pan ◽  
Jian Wu
Keyword(s):  
Numerical Modeling ◽  
Failure Mechanisms ◽  
Rock Masses ◽  
Anisotropic Rock

scholarly journals Proposal for the Assessment of Steel Truss Reliability Under Fire Conditions

2015 ◽  
Vol 61 (4) ◽  
pp. 141-154 ◽  
Author(s):  
K. Kubicka ◽  
U. Radoń
Keyword(s):  
Stiffness Matrix ◽  
Reliability Index ◽  
Failure Mechanisms ◽  
Probabilistic Approach ◽  
Reliability Model ◽  
Safety Level ◽  
Variable System ◽  
Steel Truss ◽  
Fire Conditions

The paper presents a proposal for the assessment of the reliability of steel truss (both statically determinate and indeterminate) in the persistent and accidental design situation. In the analysis, a probabilistic approach was used. The global Hasofer-Lind reliability index was employed, computed in successive time steps for the whole structure, not for individual elements. The statically determinate truss was modelled as a serial system from the reliability standpoint. For the statically indeterminate truss, kinematically admissible failure mechanisms were determined by means of the examination of the singularity of the stiffness matrix of the structure, converting the truss into a geometrically variable system. For the problem thus formulated, a serial-parallel reliability model was constructed. Monitoring the reliability index in the successive minutes of the fire makes it possible to estimate the probability of the structure failure, and to decide whether the required safety level is maintained.

scholarly journals An historical, geomechanical and probabilistic approach to rock-fall hazard assessment

2003 ◽  
Vol 3 (6) ◽  
pp. 693-701 ◽  
Author(s):  
D. Hantz ◽  
J. M. Vengeon ◽  
C. Dussauge-Peisser
Keyword(s):  
Probabilistic Approach ◽  
Rock Fall ◽  
Rock Masses ◽  
Rock Falls ◽  
Time Period ◽  
Geomechanical Analysis ◽  
Order Of Magnitude ◽  
The Given ◽  
Unstable Rock ◽  
Failure Probabilities

Abstract. A new method (HGP for Historical, Geomechanical and Probabilistic) is proposed to estimate the failure probability of potentially unstable rock masses in a homogenous area, as a function of time. Analysis of a rock falls inventory yields the mean number of rock falls which may be expected in the area for the given time period and a given volume range. According to their geomechanical features, the potentially unstable rock masses are distributed in classes corresponding to different failure probabilities. The expected number of rock falls can be expressed as a function of these unknown probabilities. Assuming that only the ratio between these probabilities can be estimated, combining the historical and geomechanical analysis allows estimating the order of magnitude of the different failure probabilities. The method gives a quantitative significance to the evaluations which are usually attributed to potentially unstable rock masses. Rock-fall hazard can then be compared with other natural hazards, such as floods or earthquakes. The method is applied to a case study of calcareous cliffs in the area of Grenoble, France.

On the role of tin underlays for the prevention of thermal grooving in thin gold films

1986 ◽  
Vol 44 ◽  
pp. 732-733
Author(s):  
Jin Young Kim ◽  
R. E. Hummel ◽  
R. T. DeHoff
Keyword(s):  
Thin Film ◽  
Free Surface ◽  
Grain Boundary ◽  
Beneficial Effect ◽  
Failure Mechanism ◽  
Failure Mechanisms ◽  
Distinct Advantage ◽  
Gold Films ◽  
Gold Thin Film

Gold thin film metallizations in microelectronic circuits have a distinct advantage over those consisting of aluminum because they are less susceptible to electromigration. When electromigration is no longer the principal failure mechanism, other failure mechanisms caused by d.c. stressing might become important. In gold thin-film metallizations, grain boundary grooving is the principal failure mechanism.Previous studies have shown that grain boundary grooving in gold films can be prevented by an indium underlay between the substrate and gold. The beneficial effect of the In/Au composite film is mainly due to roughening of the surface of the gold films, redistribution of indium on the gold films and formation of In2O3 on the free surface and along the grain boundaries of the gold films during air annealing.

Real-time cryo-deformation of polypropylene and impact-modified polypropylene in the transmission electron microscope

1993 ◽  
Vol 51 ◽  
pp. 892-893
Author(s):  
Robert C. Cieslinski ◽  
H. Craig Silvis ◽  
Daniel J. Murray
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Failure Mechanisms ◽  
Brittle Transition ◽  
Molded Part ◽  
Transmission Electron ◽  
Solvent Cast ◽  
The Impact ◽  
Annealed Copper ◽  
Dynamic Plane

An understanding of the mechanical behavior polymers in the ductile-brittle transition region will result in materials with improved properties. A technique has been developed that allows the realtime observation of dynamic plane stress failure mechanisms in the transmission electron microscope. With the addition of a cryo-tensile stage, this technique has been extented to -173°C, allowing the observation of deformation during the ductile-brittle transition.The technique makes use of an annealed copper cartridge in which a thin section of bulk polymer specimen is bonded and plastically deformed in tension in the TEM using a screw-driven tensile stage. In contrast to previous deformation studies on solvent-cast films, this technique can examine the frozen-in morphology of a molded part.The deformation behavior of polypropylene and polypropylene impact modified with EPDM (ethylene-propylene diene modified) and PE (polyethylene) rubbers were investigated as function of temperature and the molecular weight of the impact modifier.

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