scholarly journals An innovative micromechanics-based three-dimensional long-term strength criterion for fracture assessment of rock materials

2018 ◽  
Vol 12 (44) ◽  
pp. 64-81
Author(s):  
xiaoping zhou ◽  
Xiaocheng Huang ◽  
Filippo Berto
Keyword(s):  
Three Dimensional ◽  
Strength Criterion ◽  
Term Strength ◽  
Rock Materials ◽  
Fracture Assessment

A long-term strength criterion for frozen clay under complex stress states

2020 ◽  
Vol 176 ◽  
pp. 103089
Author(s):  
Dun Chen ◽  
Wei Ma ◽  
Guoyu Li ◽  
Zhiwei Zhou ◽  
Yanhu Mu
Keyword(s):  
Strength Criterion ◽  
Complex Stress ◽  
Term Strength ◽  
Frozen Clay ◽  
Stress States

scholarly journals Evaluating long-term strength of structures

2019 ◽  
Vol 23 (Suppl. 2) ◽  
pp. 477-488
Author(s):  
Ivan Volkov ◽  
Leonid Igumnov ◽  
Denis Shishulin
Keyword(s):  
Service Life ◽  
Nuclear Power ◽  
Damage Accumulation ◽  
Failure Process ◽  
Strength Criterion ◽  
Term Strength ◽  
Inelastic Behavior ◽  
Deformation And Failure ◽  
Initial Strength

The issue of evaluating strength and service life is discussed as applied to structures, the exploitation properties of which are characterized by multi-parametric nonstationary thermal mechanical effects. The main requirements to mathematical models of the related processes are formulated. In the framework of mechanics of damaged media, a mathematical model describing processes of inelastic deformation and damage accumulation due to creep is developed. The mechanics of damaged media model consists of three interconnected parts: relations defining inelastic behavior of the material accounting for its dependence on the failure process, equations describing kinetics of damage accumulation, and a strength criterion of the damaged material. The results of numerically simulating the carrying capacity of a nuclear power plant reactor vessel in the event of a hypothetical emergency are presented. Emergency conditions were modeled by applying pressure modeling the effect of melt-down, the constant internal pressure and temperature varying within the part of the vessel in question. The analysis of the obtained numerical results made it possible to note a number of characteristic features accompanying the process of deformation and failure of such facilities, connected with the time and place of the forming macrocracks, the stressed-strained state history and the damage degree in the failure zone, etc. The results of comparing the numerical and experimental data make it possible to conclude that the proposed defining relations of mechanics of damaged media adequately describe degradation of the initial strength properties of the material for the long-term strength mechanism and can be effectively used in evaluating strength and service life of structures under thermal mechanical loading.

scholarly journals CRITERIAL METHOD OF CALCULATIONS OF LONG-TERM STABILITY OF THE BOREHOLE

2018 ◽  
pp. 79-84
Author(s):  
O. A. Shipilova ◽  
S. V. Shafieva
Keyword(s):  
Strength Criterion ◽  
Oil Wells ◽  
Term Strength ◽  
Short Term ◽  
Term Stability ◽  
Long Term Stability ◽  
Short Term Strength

The article examines the possibility of applying the Mohr - Coulomb short-term strength criterion to the calculations of long-term stability of open oil wells. The results of calculation of long-term and short-term strength on the basis of the polygon of stability are analyzed.

Practical electron tomography

1995 ◽  
Vol 53 ◽  
pp. 742-743
Author(s):  
C.L. Woodcock
Keyword(s):  
Electron Tomography ◽  
Tomographic Reconstruction ◽  
Three Dimensional ◽  
3D Shape ◽  
Computational Resources ◽  
Shape Of Particles

Despite the potential of the technique, electron tomography has yet to be widely used by biologists. This is in part related to the rather daunting list of equipment and expertise that are required. Thanks to continuing advances in theory and instrumentation, tomography is now more feasible for the non-specialist. One barrier that has essentially disappeared is the expense of computational resources. In view of this progress, it is time to give more attention to practical issues that need to be considered when embarking on a tomographic project. The following recommendations and comments are derived from experience gained during two long-term collaborative projects.Tomographic reconstruction results in a three dimensional description of an individual EM specimen, most commonly a section, and is therefore applicable to problems in which ultrastructural details within the thickness of the specimen are obscured in single micrographs. Information that can be recovered using tomography includes the 3D shape of particles, and the arrangement and dispostion of overlapping fibrous and membranous structures.

Custom Presurgical Planning for Midfacial Reconstruction

2020 ◽  
Vol 36 (06) ◽  
pp. 696-702
Author(s):  
Nolan B. Seim ◽  
Enver Ozer ◽  
Sasha Valentin ◽  
Amit Agrawal ◽  
Mead VanPutten ◽  
...  
Keyword(s):  
Multidisciplinary Approach ◽  
Functional Performance ◽  
Three Dimensional ◽  
Free Tissue Transfer ◽  
Long Term Effects ◽  
Presurgical Planning ◽  
Dental Rehabilitation ◽  
Midface Reconstruction ◽  
Reconstructive Algorithm

AbstractResection and reconstruction of midface involve complex ablative and reconstructive tools in head and oncology and maxillofacial prosthodontics. This region is extraordinarily important for long-term aesthetic and functional performance. From a reconstructive standpoint, this region has always been known to present challenges to a reconstructive surgeon due to the complex three-dimensional anatomy, the variable defects created, combination of the medical and dental functionalities, and the distance from reliable donor vessels for free tissue transfer. Another challenge one faces is the unique features of each individual resection defect as well as individual patient factors making each preoperative planning session and reconstruction unique. Understanding the long-term effects on speech, swallowing, and vision, one should routinely utilize a multidisciplinary approach to resection and reconstruction, including head and neck reconstructive surgeons, prosthodontists, speech language pathologists, oculoplastic surgeons, dentists, and/or craniofacial teams as indicated and with each practice pattern. With this in mind, we present our planning and reconstructive algorithm in midface reconstruction, including a dedicated focus on dental rehabilitation via custom presurgical planning.

Subcritical Crack Growth and Long-Term Strength in Rock and High-Strength and Ultra Low-Permeability Concrete

2009 ◽  
Vol 58 (6) ◽  
pp. 525-532 ◽  
Author(s):  
Yoshitaka NARA ◽  
Masafumi TAKADA ◽  
Daisuke MORI ◽  
Hitoshi OWADA ◽  
Tetsuro YONEDA ◽  
...  
Keyword(s):  
Crack Growth ◽  
Subcritical Crack Growth ◽  
High Strength ◽  
Low Permeability ◽  
Term Strength
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