scholarly journals Накопление повреждений при статическом деформировании твердого тела регулярного строения: микротрещины, неотрелаксированные напряжения

2020 ◽  
Vol 46 (23) ◽  
pp. 51
Author(s):  
А.М. Лексовский ◽  
Б.Л. Баскин ◽  
Г.Н. Губанова ◽  
В.Е. Юдин
Keyword(s):  
Acoustic Emission ◽  
Internal Friction ◽  
Elastic Deformation ◽  
Metastable State ◽  
Equilibrium Composition ◽  
Nonlinear Mechanism ◽  
Microcrack Formation ◽  
Heterogeneous Solid

Abstract: Using the methods of acoustic emission in the variant of linear location and internal friction, it is shown that when an initially equilibrium composition of the CFRP type is stretched, unrelaxed stresses accumulate in the places of intense microcrack formation. This is due to the incomplete completeness of the relaxation redistribution of the accumulated energy / elastic deformation by a nonlinear mechanism. The increasing level of unrelaxed stresses inevitably transforms the heterogeneous solid into a metastable state. As a result, the dissipative capacity of the system as a whole is reduced and the probability of a nonequilibrium crack appears.

Relationship between acoustic emission and microcrack formation in single crystals of Hadfield steel

2018 ◽  
Author(s):  
D. V. Lychagin ◽  
A. V. Filippov ◽  
E. N. Moskvichev ◽  
O. S. Novitskaia ◽  
E. A. Kolubaev
Keyword(s):  
Acoustic Emission ◽  
Single Crystals ◽  
Hadfield Steel ◽  
Microcrack Formation

Correlation between Acoustic Emission and Internal Friction in Materials

2006 ◽  
Vol 13-14 ◽  
pp. 313-322 ◽  
Author(s):  
Alexei Vinogradov
Keyword(s):  
Acoustic Emission ◽  
Stress Relaxation ◽  
Internal Friction ◽  
Metal Matrix ◽  
Matrix Composites ◽  
Strain Accumulation ◽  
Strain Fracture ◽  
The Difference ◽  
The Relationship ◽  
Good Agreement

The relationship between acoustic emission and internal friction is investigated during cyclic deformation of copper single- and poly-crystals at intermediate amplitudes. Good agreement between these two phenomena has been demonstrated in all materials tested as long as the stress relaxation occurs uniformly within the sample whereas the difference between them becomes pronounced when strain/fracture localisation takes place. The similarity between acoustic emission and internal friction can be extended to materials deforming without appreciable plastic deformation, such as metal matrix composites where the main source of stress relaxation and strain accumulation is the particle breakage. The significance of the relation between internal friction and acoustic emission for understanding of fundamentals of AE is discussed.

Deformation and Acoustic Emission during Nanoindentation on Single Crystal MgO (001) Plane

2009 ◽  
Vol 76-78 ◽  
pp. 404-409 ◽  
Author(s):  
Zhi Gang Dong ◽  
Han Huang ◽  
Ren Ke Kang
Keyword(s):  
Acoustic Emission ◽  
Single Crystal ◽  
Energy Release ◽  
Elastic Deformation ◽  
Elastic Energy ◽  
Elastoplastic Deformation ◽  
Acoustic Emission Monitoring ◽  
Emission Monitoring ◽  
Three Stages

Nanoindentation tests with the aid of acoustic emission monitoring were performed on single crystal MgO (001) plane to investigate the deformation of MgO under high indentation pressures. The results indicated that the deformation of MgO under nanoindentation with a sharp indenter could be classified into three stages: elastic deformation, elastoplastic deformation, and fragmentation. The elastic energy release and fracture occurred could be identified using acoustic emission signals.

Damage Evaluation of 16Mn Steel in Tensile Test

2011 ◽  
Vol 291-294 ◽  
pp. 1303-1306
Author(s):  
Hong Wei Wang ◽  
Hong Yun Luo ◽  
Zhi Yuan Han ◽  
Qun Peng Zhong
Keyword(s):  
Acoustic Emission ◽  
Tensile Test ◽  
Elastic Deformation ◽  
Steel Plate ◽  
Steel Structures ◽  
The State ◽  
Cusp Catastrophe ◽  
Catastrophe Model ◽  
Cusp Catastrophe Model ◽  
16Mn Steel

This study was focused on damage monitoring and estimation of 16Mn steel structures. This study used acoustic emission (AE) cusp catastrophe model to estimate the time at which the state of 16Mn steel will change from elastic deformation to yield deformation. Firstly, the tensile test of 16Mn steel plate specimens was monitored with acoustic emission technique. Secondly, a acoustic emission cusp catastrophe model was establish based on cusp catastrophe theory and acoustic emission signals. Finally, some catastrophe time was estimated with AE cusp catastrophe model. At this catastrophe time, the state of 16Mn steel plate specimen might change from elastic deformation to yield deformation. The experimental results show that AE cusp catastrophe model can estimate the time at which the state might change from elastic deformation to yield deformation of 16Mn steel in tensile test.

Modeling of a joint-type flexible endoscope based on elastic deformation and internal friction

2019 ◽  
Vol 33 (19) ◽  
pp. 985-995
Author(s):  
Yuanyuan Zhou ◽  
Guohao Jiang ◽  
Cheng Zhang ◽  
Zhidong Wang ◽  
Zhongtao Zhang ◽  
...  
Keyword(s):  
Internal Friction ◽  
Elastic Deformation ◽  
Flexible Endoscope

Estimation of the Limit State Criterion for Steels C1020 and A 516-55 with V-Notch under Quasistatic Loading Using Acoustic Emission Control

2019 ◽  
Vol 945 ◽  
pp. 585-591
Author(s):  
M.M. Zakirnichnaya ◽  
O.R. Abdulganieva ◽  
D.A. Yudicheva
Keyword(s):  
Acoustic Emission ◽  
Room Temperature ◽  
Oil And Gas ◽  
Limit State ◽  
Maximum Size ◽  
Pulse Amplitude ◽  
High Amplitude ◽  
Low Alloy Steels ◽  
Microcrack Formation ◽  
State Criterion

There is a need to determine the stresses value for responsible designs in the oil and gas refining, petrochemical and chemical industries, at which the defect reaches its maximum size. This stress value can be taken as the limit state criterion for strength calculations of vessels and apparatus. The article presents a technique for determining the limit state criterion for carbonaceous and low-alloy steels using the example of steels C1020 and A 516-55 in the state of delivery. As a limit state criterion it is proposed to use the stress value corresponding to the microcrack formation moment. The studies are based on the uniaxial tension tests results at room temperature of flat samples with V-shaped stress concentrators of 2 mm deep, accompanied by an acoustic emission nondestructive testing method. Based on the obtained pulse amplitude and pulse energy dependences on time in the process of testing and fractographic studies, a technique for estimating acoustic emission signals was developed to determine the microcrack formation moment for test steels. Stress values that can be taken as the limit state criterion for steels C1020 and A 516-55 in the delivery state for strength calculations vessels and apparatus are determined using the developed experimentally technique based on the high-amplitude acoustic emission to low-amplitude signals ratio. With the help of specimen fractures fractographic analysis the legitimacy of using the developed technique is justified. Thus, at room temperature for steel C1020, the stress at which a microcrack begins to form is 420 MPa, for steel A 516-55 it is 455 MPa.

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