ON THE CRACK PROPAGATION IN STRUCTURAL MATERIALS AND ROCKS FROM THE STANDPOINT OF SYNERGETICS

Purpose: The aim of the work is to analyze from the standpoint of the principles of synergetics the experimental results of the destruction of solid polymers, steels and rocks.Methodology: To analyze experimental data on the propagation of fracture cracks during quasi-static and pulse stretching and bending of samples of solid polymers (PMMA), steels and concrete, taking into account the stock of elastic or elastic-plastic energy at the time of failure. Analyze the shape and quantitative characteristics of dissipative structures that are formed in a solid body when the crack propagates through the material.Findings: Analysis of the distribution modes of county and fast trainings in polymeric materials (PMMA), tool steels and concrete according to different schemes and modes of loading samples shows that the abrupt nature of their movement with periodic trading speed of private or zero is the basis of genealogical organization. The nature of this phenomenon is based on the principles of synergetic, which determine the principle of minimum energy production.Originality: It is shown that the patterns of crack propagation in solid polymers, metals and rocks have a synergistic nature. A working hypothesis on the synergetic mechanism of softening and deformation control of brittle dilatation rocks near underground plants is formulated.Practical implications: It is shown that the nature of the distribution of county cracks during PMMA fracturing, as well as rapid cracks during pulse stretching and bending flat samples of PMMA and the capital as a whole are subject to energy principles, in particular the principle of minimum energy production. It is obvious that for the qualitative and quantitative description of structural changes and destructive deformation of rocks near underground cultivations there is a lack of models of solid environment mechanics. In practice, you need to listen to the abrupt nature of the processes and cooperative effects.

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Quantitative description of micro-structural changes in lead-free solder alloys

2006 8th Electronics Packaging Technology Conference ◽

10.1109/eptc.2006.342748 ◽

2006 ◽

Cited By ~ 2

Author(s):

Wolfgang Muller ◽

Thomas Bohme

Keyword(s):

Structural Changes ◽

Quantitative Description ◽

Lead Free ◽

Lead Free Solder ◽

Solder Alloys ◽

Free Solder

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Fatigue crack propagation analyses based on plastic energy approach

Computational Materials Science ◽

10.1016/j.commatsci.2007.04.016 ◽

2008 ◽

Vol 41 (3) ◽

pp. 344-349 ◽

Cited By ~ 15

Author(s):

M. Mazari ◽

B. Bouchouicha ◽

M. Zemri ◽

M. Benguediab ◽

N. Ranganathan

Keyword(s):

Fatigue Crack ◽

Crack Propagation ◽

Fatigue Crack Propagation ◽

Energy Approach ◽

Plastic Energy

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On the Influence of the Corner Singularity on Kinking Mixed-Mode Crack Propagation

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.348-349.585 ◽

2007 ◽

Vol 348-349 ◽

pp. 585-588

Author(s):

Henning Schütte ◽

Kianoush Molla-Abbasi

Keyword(s):

Stress Intensity ◽

Crack Propagation ◽

Crack Growth ◽

Stress Intensity Factors ◽

Mixed Mode ◽

Small Scale ◽

Intensity Factors ◽

Plastic Energy ◽

Mixed Mode Crack ◽

The Impact

The aim of the presentation is to highlight the influence of the kink, developing at the beginning of mixed-mode crack growth, on the propagation behavior of the crack. Le et al. [1] have shown that the variational principle of a body containing a crack results in the principle of maximum energy release rate incorporating the stress intensity factors of the kinked crack. Here the influence of the kink and the kinking angle, resulting in a singular field around the corner, on the crack growth is analyzed. The generalized stress intensity factors at the kinks corner are computed with the help of a FEM strategy. The influence of these on the T-stresses and the plastic energy dissipated at the kink is determined using a small scale yielding approach. The impact of these results on mixed-mode crack propagation is discussed.

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Plastic Energy Required for Fatigue Failure of Specimens Containing Cracks

Journal of Engineering Materials and Technology ◽

10.1115/1.3443278 ◽

1975 ◽

Vol 97 (2) ◽

pp. 172-178 ◽

Cited By ~ 1

Author(s):

Thang Bui-Quoc ◽

Andre Biron

Keyword(s):

Experimental Data ◽

Crack Propagation ◽

Hysteresis Loops ◽

Mean Value ◽

Repeated Loading ◽

Plastic Energy ◽

Propagation Law ◽

The Mean ◽

Damage Rule ◽

Propagation Stage

A study is conducted to determine the plastic energy absorbed by a material subjected to cyclic loading during the crack propagation stage. The analysis is based on Liu’s elastoplastic solution for calculating the plastic energy around the crack tip combined with a modified crack propagation law. The plastic energy per cycle Δw is found to be dependent upon the fatigue crack length and therefore varies with the number of applied cycles. The mean value of this energy corresponds to the plastic energy obtained by measuring the area within the stress-strain hysteresis loops of the material under repeated loading. If fatigue damage is based on plastic energy, the trend of variation of Δw with the applied cycles in the present analysis shows that the application of the linear damage rule (such as Miner’s law) should be more successful in the low-cycle region than in the high-cycle region. This is consistent with experimental data.

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Centriole cycle in Chinese hamster ovary cells as determined by whole-mount electron microscopy.

The Journal of Cell Biology ◽

10.1083/jcb.91.3.814 ◽

1981 ◽

Vol 91 (3) ◽

pp. 814-821 ◽

Cited By ~ 170

Author(s):

R Kuriyama ◽

G G Borisy

Keyword(s):

Electron Microscopy ◽

Dna Synthesis ◽

Chinese Hamster Ovary ◽

Structural Changes ◽

Morphological Changes ◽

Chinese Hamster Ovary Cells ◽

Quantitative Description ◽

Chinese Hamster ◽

Ovary Cells ◽

Whole Mount

In interphase Chinese hamster ovary (CHO) cells, the centrosome is attached to the nucleus very firmly. This nuclear-centrosome complex is isolated as a coherent structure by lysis and extraction of cells with Triton X-100 in a low ionic strength medium. Under these conditions, the ultrastructure of the centrioles attached to the nucleus can be discerned by electron microscopy of whole-mount preparations. The structural changes of the centrioles as a function of the cell cycle were monitored by this technique. Specifically, centriolar profiles were placed into six categories according to their orientation and the length ratio of daughter and parent centrioles. The proportion of centrioles in each category was plotted as a frequency histogram. The morphological changes in the centriole cycle were characterized by three distinguishable events: nucleation, elongation, and disorientation. The progress of centrioles through these stages was determined in synchronous populations of cells starting from S or M phase, in cells inhibited in DNA synthesis by addition of thymidine, and in cytoplasts. The results provide a quantitative description of the events of the centriole cycle. They also show that, in complete cells, nucleation, elongation, and disorientation are not dependent upon DNA synthesis. However, in cytoplasts, although elongation and disorientation occur as in normal cells, nucleation is blocked. Procentriole formation appeared to be inhibited by the removal of the nucleus. We suggest that coordination of centriole replication and nuclear replication may depend upon a signal arising from the nucleus.

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Crack propagation studies of bulk polymeric materials in the scanning electron microscope

Journal of Materials Science Letters ◽

10.1007/bf00720070 ◽

1984 ◽

Vol 3 (1) ◽

pp. 39-43 ◽

Cited By ~ 9

Author(s):

S. Bandyopadhyay

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

Crack Propagation ◽

Polymeric Materials ◽

Scanning Electron

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Analyzing the Foreign Economic Activities of Ukraine and the Structure of Export-Import Operations with Plastic Pipes

Business Inform ◽

10.32983/2222-4459-2020-9-29-36 ◽

2020 ◽

Vol 9 (512) ◽

pp. 29-36

Author(s):

M. S. Rakhman ◽

◽

O. V. Zaika ◽

Keyword(s):

Structural Changes ◽

Raw Materials ◽

Polymeric Materials ◽

Foreign Market ◽

Economic Activities ◽

Average Volume ◽

Pricing Policy ◽

Goods And Services ◽

Polyethylene Pipes ◽

The Impact

Polyethylene (PE) and polyvinyl chloride (PVC) are used in many areas of human activity, in the production of various goods, which is carried out mainly on the basis of imported raw materials. This production is almost entirely focused on the domestic consumption, and the pricing policy directly depends on customs duties and taxes. On the Ukrainian market are presented imported fabricated products with uprated specification, in particular, pipe products made of polymeric materials. The article is aimed at studying the volumes and structure of export-import operations of Ukraine in terms of the group «Polymeric materials, plastics and products from them», identifying problems and prospects of Ukrainian producers of pipe products and their participation in foreign economic activities. The analysis of structural changes in volumes and balance of the foreign trade in goods and services of Ukraine in dynamics is carried out; the volume of export-import operations in goods is determined; averages for the period are computed. The participation of Ukrainian enterprises in the implementation of foreign economic activities is characterized, including: quantity, regional placement in the territory of the country, the average volume of operations. The volumes and dynamics of export-import operations in the group 39 «Plastics, polymeric materials», both the commodity and the geographical structure are analyzed. The authors consider the main producers of fabricated polymer-pipe products together with the producers of domestic raw materials, their proportion in the sale of goods in the foreign market; the suppliers of imported raw materials and the impact of changes in customs tariffs and fees on prices. The range of average export-import prices for 1 kg of polyethylene pipes for the top five countries is calculated. Market problems are identified and the relevant recommendations are made.

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Quantification of the Spatial Organization of the Nuclear Lamina as a Tool for Cell Classification

ISRN Molecular Biology ◽

10.1155/2013/374385 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6

Author(s):

Christiaan H. Righolt ◽

Diana A. Zatreanu ◽

Vered Raz

Keyword(s):

Nuclear Envelope ◽

Spatial Organization ◽

Structural Changes ◽

Structural Integrity ◽

Quantitative Description ◽

Three Dimensional ◽

Nuclear Lamina ◽

Cellular Functions ◽

Cell Classification ◽

Nuclear Stability

The nuclear lamina is the structural scaffold of the nuclear envelope that plays multiple regulatory roles in chromatin organization and gene expression as well as a structural role in nuclear stability. The lamina proteins, also referred to as lamins, determine nuclear lamina organization and define the nuclear shape and the structural integrity of the cell nucleus. In addition, lamins are connected with both nuclear and cytoplasmic structures forming a dynamic cellular structure whose shape changes upon external and internal signals. When bound to the nuclear lamina, the lamins are mobile, have an impact on the nuclear envelop structure, and may induce changes in their regulatory functions. Changes in the nuclear lamina shape cause changes in cellular functions. A quantitative description of these structural changes could provide an unbiased description of changes in cellular function. In this review, we describe how changes in the nuclear lamina can be measured from three-dimensional images of lamins at the nuclear envelope, and we discuss how structural changes of the nuclear lamina can be used for cell classification.

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