scholarly journals Thermo-ultrasound method for determining the damage of structural material

2018 ◽  
Vol 224 ◽  
pp. 02027 ◽  
Author(s):  
Alexander Gonchar ◽  
Vasily Mishakin ◽  
Konstantin Kurashkin
Keyword(s):  
Plastic Deformation ◽  
Strength Properties ◽  
Elastic Wave Velocity ◽  
Ultrasonic Waves ◽  
Martensitic Phase ◽  
Steel 12Kh18n10t ◽  
Ultrasound Method ◽  
Longitudinal And Shear Waves ◽  
Aisi 321 ◽  
The Relationship

The effect of plastic strain and temperature on the longitudinal and shear waves velocity of austenitic stainless steel 12Kh18N10T (analogue AISI 321) is investigated. Cryogenic corrosion-resistant austenitic steel 12Kh18N10T is interesting due to the fact, that during plastic deformation a martensitic phase is formed. The martensitic phase significantly changes the electromagnetic, elastic and strength properties of the entire material. The formation of a new phase in conjunction with the process of plastic deformation has a significant effect on the temperature dependence of the elastic wave velocity. As a result of the studies, numerical values of the temperature-velocity factor for longitudinal and shear ultrasonic waves in steel 12Kh18N10T were obtained. The relationship between changes of the magnetic phase and temperature-velocity factor is suggested; it can be used for determining the material damage by the ultrasound method.

Strength Properties of Activated Hwangtoh Mortars

2010 ◽  
Vol 168-170 ◽  
pp. 709-715
Author(s):  
Dongsik Oh ◽  
Doheom Song ◽  
Seongseok Go
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Building Materials ◽  
Strength Properties ◽  
Mixing Conditions ◽  
Substitution Ratio ◽  
Pozzolanic Properties ◽  
The Relationship ◽  
Furnace Slag

Hwangtoh (loess) has pozzolanic properties that mean it can be used as a cement admixture when activated at high temperatures, and that it can be used in combination with building materials such as fly ash or blast furnace slag. This study aimed to analyze the relationship between the compressive strength and the brick bond strength of various mortars containing hwangtoh, and also to find the optimum mixing conditions for the use of hwangtoh. It was found that the mortars’ strength properties are significantly influenced by the water/cement ratio W/C and the activated hwangtoh substitution ratio. We recommend the following materials and mixing conditions: W/C 60%, a cement substitution ratio of activated hwangtoh of 20 ~ 25%, and the addition of 10% blast furnace slag to improve the compressive strength of such mortars.

scholarly journals AN INVESTIGATION ON THE EFFECTS OF MICRO-PARAMETERS ON THE STRENGTH PROPERTIES OF ROCK

2021 ◽  
Vol 36 (1) ◽  
pp. 111-119
Author(s):  
Behzad Jafari Mohammadabadi ◽  
Kourosh Shahriar ◽  
Hossein Jalalifar ◽  
Kaveh Ahangari
Keyword(s):  
Mechanical Properties ◽  
Numerical Simulation ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Friction Coefficient ◽  
Critical Stress ◽  
Friction Angle ◽  
Strength Properties ◽  
Brazilian Tensile Strength ◽  
The Relationship

Rocks are formed from particles and the interaction between those particles controls the behaviour of a rock’s mechanical properties. Since it is very important to conduct extensive studies about the relationship between the micro-parameters and macro-parameters of rock, this paper investigates the effects of some micro-parameters on strength properties and the behaviour of cracks in rock. This is carried out by using numerical simulation of an extensive series of Uniaxial Compressive Strength (UCS) and Brazilian Tensile Strength (BTS) tests. The micro-parameters included the particles’ contact modulus, the contact stiff ness ratio, bond cohesion, bond tensile strength, the friction coefficient and the friction angle, and the mechanical properties of chromite rock have been considered as base values of the investigation. Based on the obtained results, it was found that the most important micro-parameters on the behaviour of rock in the compressive state are bond cohesion, bond tensile strength, and the friction coefficient. Also, the bond tensile strength showed the largest effect under tensile conditions. The micro-parameter of bond tensile strength increased the rock tensile strength (up to 5 times), minimized destructive cracks and increased the corresponding strain (almost 2.5 times) during critical stress.

The Influence of Severe Plastic Deformation Process on Structure and Properties of AZ 31 Alloy after Selected Heat Treatment

2018 ◽  
Vol 275 ◽  
pp. 134-146
Author(s):  
Stanislav Rusz ◽  
Ondřej Hilšer ◽  
Stanislav Tylšar ◽  
Lubomír Čížek ◽  
Tomasz Tański ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Structure Refinement ◽  
Hardness Measurement ◽  
Az31 Alloy ◽  
Strength Properties ◽  
Aviation Industry ◽  
Initial State

The technology of structure refinement in materials with the aim of achieving substantial mechanical properties and maintaining the required plasticity level is becoming increasingly useful in industrial practice. Magnesium alloys are very progressive materials for utilization in practice thanks to their high strength-to-weight ratios (tensile strength/density). The presented paper analyses the effect of the input heat treatment of the AZ31 alloy on the change of structure and strength properties through the process of severe plastic deformation (SPD), which finds an increasing utilization, especially in the automotive and aviation industry. For the study of the influence of the SPD process (ECAP method) on the properties of the AZ31 alloy, two types of thermal treatment of the initial state of the structure were selected. The analysis of the structure of the AZ31 alloy was performed in the initial state without heat treatment and subsequently after heat treatment. In the next part, the influence of the number of passes on the strengthening curves was evaluated. Mechanical properties of the AZ31 alloy after ECAP were evaluated by hardness measurement and completed by structure analysis.

True Stress and Shakedown Analysis of Pressure Vessel which under Cyclic Loading to Plastic Deformation

2014 ◽  
Vol 590 ◽  
pp. 8-12
Author(s):  
Xiao Liang Jia ◽  
Yi Liang Zhang ◽  
Jing Wang ◽  
Chun Bo Wang
Keyword(s):  
Plastic Deformation ◽  
Constitutive Model ◽  
Pressure Vessel ◽  
Axial Stress ◽  
Water Pressure ◽  
True Strain ◽  
Test System ◽  
True Stress ◽  
Plastic Shakedown ◽  
The Relationship

The aim of this study is to discuss the plastic shakedown and true stress of the cyclically loaded pressure vessel. A thin-walled cylinder pressure vessel is made according to actual working state and a water pressure test system is built. The vessel is loaded to different strain levels of plastic deformation first. Then it is loaded cyclically to shakedown state. The relationship between plastic strain and shakedown range is given based on numerous experiments. The constitutive model of the true stress-true strain of the vessel is obtained. The experimental results show that the ratcheting obviously occurred when the vessel is cyclically loaded to plastic deformation. The true stress-strain constitutive model which is presented in this paper can show appropriately the constitutive relation of the vessel when it is under multi-axial stress state. The application of uniaxial shakedown constitutive model has been demonstrated in this study.

Finish Roll Forming of Spur Gears for High Efficiency

2000 ◽  
Author(s):  
Seizo Uematsu ◽  
Masana Kato
Keyword(s):  
Plastic Deformation ◽  
High Speed ◽  
High Efficiency ◽  
Tooth Profile ◽  
Roll Forming ◽  
Spur Gears ◽  
Design Data ◽  
Constant Center ◽  
The Relationship ◽  
Center Distance

Abstract Finish roll forming under the constant center distance by forced feed of tool can be conceived as a method of eliminating errors in conventional form rolling under constant loads. This method generates a high-precision tooth profile by low-speed form rolling when a high rigid screw or cam is used as loading parts. In this study, the high-speed rolling conditions of this method for necessary to be applied in practical situations are discussed. The following conclusions are obtained. When the following design data are given (module, number of teeth, addendum modification coefficient, prescribed design precision, and material characteristics), the accuracy of rolled gear can be predicted from the relationship between the required feed for the tool and the theoretically calculated plastic deformation on the tooth profile. These conclusions are verified experimentally. For example, the tooth accuracy of rolled gears with module 5 can improve from JIS class 3 to JIS class 0 or 1 when the load Fmax is 4 to 5kN and the pitch line velocity is 7 m/min.

scholarly journals Ultrasonic Properties of Plastically Deformed Ice

1975 ◽  
Vol 15 (73) ◽  
pp. 161-169 ◽  
Author(s):  
J. Tatibouet ◽  
R. Vassoille ◽  
J. Perez
Keyword(s):  
Plastic Deformation ◽  
Physical Properties ◽  
Sound Velocity ◽  
Single Crystals ◽  
Stress Waves ◽  
Ultrasonic Waves ◽  
Velocity Of Sound ◽  
Propagation Characteristics ◽  
Ultrasonic Properties ◽  
Crystalline Materials

AbstractMany authors have used propagation of ultrasonic waves in ice for glaciological studies. This propagation is characterized by the velocity of sound and by the attenuation of stress waves. In crystalline materials, these two characteristics depend on structural slate. In particular plastic deformation gives velocity and attenuation variations.We have measured the sound velocity and attenuation of ultrasonic waves in strained specimens of ice (single crystals and polycrystals). These measurements done between 100 and 273 K at a frequency of 5 MHz show that plastic deformation leads to an increase of attenuation arid an increase of velocity. Annealing treatments at 271 K cause recovery of propagation characteristics. The variation in attenuation can be interpreted by the theory of dislocations and this interpretation is supported by our data on the influence of frequency on this increase of attenuation induced by plastic deformation, but the theory of dislocations implies a decrease of modulus, i.e. of velocity, hence we must postulate that an added phenomenon screens the effect of dislocations. That phenomenon could be connected with ageing effects observed on different physical properties of ire and may be due to modification of protonic arrangement or creation of interstitials during plastic deformation. Thus our experiments show that it is necessary to be careful in using results determined from the propagation of ultrasonic waves in ice.

Sign in / Sign up

Export Citation Format

Share Document