Plastic Behavior of Laser Cladding Sample under Repeated-Impact Load

2010 ◽  
Vol 426-427 ◽  
pp. 294-298
Author(s):  
Shi Hong Shi ◽  
Ge Yan Fu
Keyword(s):  
Plastic Deformation ◽  
Impact Load ◽  
Base Material ◽  
Medium Carbon Steel ◽  
Plastic Behavior ◽  
Static Fatigue ◽  
Repeated Impact ◽  
Deformation Degree ◽  
Degree Of Deformation ◽  
The Impact

Low stress repeated impact experiments and test were carried out on medium carbon steel and stainless steel samples which is clad with high-strength Co-based or Ni-based alloy. The results showed that under low stress repeated impact load, which is much lower than the yield strength of material, plastic deformation will be occurred on the coating and part of its below base material. The average plastic deformation degree caused by each impact is increased at first, and then declined with the increase of impact times. Accumulated impact will lead to macroscopic plastic deformation and material hardening. The degree of deformation and the size of deformation area are related to the impact stress value and the material’s strength. The degree of deformation and hardening decline from the exterior to the interior, and only occur on the impact surface and a certain depth below, forming a ‘deformable area’. Based on our analysis, we consider that low stress repeated impact deformation is a kind of accumulative fatigue damage. The energy absorbed by material under repeated impact load, is larger than that absorbed at the same peak value of stress under static load or static fatigue load. Moreover, the energy absorbability is inversely proportional to the impact distance. Repeated impact may increase the movability of atom, reduce the critical shearing stress, that make the dislocation be initiated and increased easily.

The Plastic Deformation and Enhancement of 304Stainless Steel under Low Stress Repeat Impact

2013 ◽  
Vol 419 ◽  
pp. 316-320
Author(s):  
Zheng Dong He ◽  
Jian Shi ◽  
Ge Yan Fu
Keyword(s):  
Plastic Deformation ◽  
Performance Enhancement ◽  
Impact Load ◽  
Impact Loads ◽  
Yield Limit ◽  
Repeated Impact ◽  
Engineering Applications ◽  
Gradient Coating ◽  
The Impact ◽  
Application Scope

In engineering applications, many key components will fail with macroscopic accumulated plastic deformation, repeated impact loads, even though the stress is far less than the material yield limit. This kind of load can be called low stress repeated impact load in this study. It is observed that the plastic deformation of the material is mainly manifested in closer to the site from the collision surface. The strain decreases with the increasing depth from the surface, and it will be smaller and smaller with the increasing number of the impact. Finally, the strain tends to be stable, which means the material will no longer be deformed[1]. Take the method of preparation of the exponential gradient coating on 304stainless steel for performance enhancement, in order to satisfy and expand its application scope and conditions.

Study on Evolution of Plastic Deformation of Brass Band under Impact Load

2017 ◽  
Vol 753 ◽  
pp. 222-227
Author(s):  
Jun Hui Yin ◽  
Chao Xiong ◽  
Hui Yong Deng ◽  
Yan Long Zhang
Keyword(s):  
Plastic Deformation ◽  
Growth Stage ◽  
Impact Load ◽  
Recrystallization Process ◽  
Brass Band ◽  
Sexual Characteristics ◽  
Surface Metal ◽  
Band Deformation ◽  
The Impact ◽  
Meso Scale

During the moving stage of the projectile, the impact load produced by the detonation of the explosive powder acts on the ribbon, causing the plastic band deformation to occur rapidly and the surface temperature rapidly increases. In this paper, the evolution mechanism of the plastic deformation of brass band is studied, and the recrystallization process of the surface metal is still at the meso-scale scale. The recrystallization and grain growth stage sexual characteristics.

scholarly journals Impact Response of Hammerhead Pier Fibrous Concrete Beams Designed with Topology Optimization

2020 ◽  
Author(s):  
Meivazhisalai Parasuraman Salaimanimagudam ◽  
Covaty Ravi Suribabu ◽  
Gunasekaran Murali ◽  
Sallal R. Abid
Keyword(s):  
Topology Optimization ◽  
Concrete Beams ◽  
Impact Load ◽  
Impact Resistance ◽  
Adaptive Mesh ◽  
Impact Response ◽  
Adaptive Meshing ◽  
Repeated Impact ◽  
Ductility Ratio ◽  
The Impact

Reducing the weight of concrete beams is a primary (beyond strength and durability) concern of engineers. Therefore, this research was directed to investigate the impact response of hammerhead pier concrete beams designed with density-based method topology optimization. The finite element topology optimization was conducted using Autodesk fusion 360 considering three different mesh sizes of 7 mm, 10 mm, and adaptive meshing. Three optimized hammerhead beam configurations; HB1, HB2, and HB3, respectively, with volume reductions greater than 50 %. In the experimental part of this research, nine beams were cast with identical size and configuration to the optimized beams. Three beams, identical to the optimized beams, were tested under static bending for verification purposes. In comparison, six more beams, as in the preceding three beams but without and with hooked end steel fibers, were tested under repeated impact load. The test results revealed that the highest flexural capacity and impact resistance at crack initiation and failure were recorded for the adaptive mesh beams (HB3 and HB3SF). The failure impact energy and ductility ratio of the beam HB3SF was higher than the beams HB1SF and HB2SF by more than 270 %. The results showed that the inclusion of steel fiber duplicated the optimized beam’s impact strength and ductility several times. The failure impact resistance of fibrous beams was higher than their corresponding plain beams by approximately 2300 to4460 %, while their impact ductility ratios were higher by 6.0 to 18.1 times.

Microstructure and Impact Load Performance of Friction Stir Welded Joint of AZ31B Magnesium Alloy

2020 ◽  
Vol 866 ◽  
pp. 54-62
Author(s):  
Hong Feng Wang ◽  
Sheng Rong Liu ◽  
Xiao Le Ge ◽  
Jia Fei Pu ◽  
Lei Bao ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Magnesium Alloy ◽  
Impact Load ◽  
Base Material ◽  
Welding Parameters ◽  
Loading Test ◽  
Az31b Magnesium Alloy ◽  
Friction Stir ◽  
Joint Area ◽  
The Impact

10mm thickness AZ31B magnesium alloy was used as the friction stir welding object in this study. Different welding joints were obtained by setting different friction stir welding parameters. Metallographic analysis and impact loading test were carried out on the joint area. The experiment results show that (i) when the rotational speed of the stirring head is 600rpm and the welding speed is 120mm/min, the microstructure of the joint has the characteristics of compactness, thinning, and large-area twinning, which is beneficial to improve the plasticity of the joint area; (ii) the impact load of the joint is the highest, but lower than that of the base material, which is 95.5% of the base material; (iii) the fracture of impact specimen presents ductile fracture.

scholarly journals Ultrasonic detection of spall damage induced by low-velocity repeated impact

2012 ◽  
Vol 2 (4) ◽  
Author(s):  
Naoya Nishimura ◽  
Katsuhiko Murase ◽  
Toshihiro Ito ◽  
Takeru Watanabe ◽  
Roman Nowak
Keyword(s):  
Medium Carbon Steel ◽  
Impact Testing ◽  
Acoustic Microscopy ◽  
Tensile Failure ◽  
Ductile Material ◽  
Low Velocity ◽  
Damage Development ◽  
Repeated Impact ◽  
Spall Damage ◽  
The Impact

AbstractThis paper address the examination of spall damage in medium carbon steel subjected to a repeated impact testing. The experiments were performed well below the threshold spall-stress of 2.6 GPa and the damage introduced in the subsurface volume was investigated using the low frequency scanning acoustic microscopy. Based on B- and C-scan images (the images taken along and perpendicular to the impact surface) we made a qualitative and semi-quantitative evaluation of the damage type (voids in a ductile material or cracks in a brittle one) and its distribution. We found the spall damage development dependent on the amplitude and the duration of the stress pulses. In particular, we proved that the high, long stress pulses induce damage that resembles tensile failure of material, in which voids or cracks nucleate along the spall plane to form macro-cracks. This explains why spall-damage is not seen when the first impact is below the characteristic threshold spall-stress. However, when the tests consist of more than four impacts the spall damage is produced already under stress below the threshold-value.

Coercimetric Quality Testing of Steel Parts. Ural School of Coercimetry

NDT World ◽  
2015 ◽  
Vol 18 (4) ◽  
pp. 9-13
Author(s):  
Муриков ◽  
Sergey Murikov ◽  
Костин ◽  
Vladimir Kostin ◽  
Сташков ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Coercive Force ◽  
Hardened Layer ◽  
Scientific School ◽  
Deformation Degree ◽  
Practical Applications ◽  
Quality Testing ◽  
Hardened Layer Thickness ◽  
The Impact

The article shows the main areas of application coercimetric NDT method. The article presents historical information about the method founders who represents the Ural scientific school of magnetism. The main limitations of the method and practical applications of one-parameter and multiparameter coercimetric techniques are shown. Problems of magnetic quality inspection of quenched and tempered steels with different carbon contents and different degrees of alloying are considered. The possibility of monitoring the quality of steel products surface hardening with the use of external converters is demonstrated. Guidelines for external electromagnet size selection in dependence on a hardened layer thickness are presented. The brief analysis of the impact of current and residual stresses on the coercive force of steel products has been fulfilled. Problems of coercimetric inspection of stresses and steel plastic deformation degree are indicated; these problems are connected with varied behaviour of the coercive force under elastic extension and at high degrees of plastic deformation in the stage of pre-destruction. The originally developed technique for coercimetric quality control of forming rolls is presented. Information about modern coercimeters developed at the Institute of Metal Physics is provided.

Impact Deformation Model of Thin-Walled Shell Filled with Explosive under High Axial Shock Overload

2013 ◽  
Vol 455 ◽  
pp. 279-285
Author(s):  
Xiao Xia Sun ◽  
Wei Liu ◽  
Rui Qi Shen ◽  
Ying Hua Ye ◽  
Li Zhi Wu
Keyword(s):  
Plastic Deformation ◽  
Impact Damage ◽  
Plastic Deformation Zone ◽  
Deformation Model ◽  
Deformation Degree ◽  
Impact Stress ◽  
Gas Gun ◽  
Impact Deformation ◽  
Thin Walled ◽  
The Impact

The thin-walled shell axial impact deformation of one-leg electric detonator with different density charge was studied. The impact stress was analyzed, and on the basis of kinetic theory the impact deformation model was established for the thin-walled shell filled with explosive. The experiments were verified at 60 000g, 80 000g, 100 000g and 120 000g by gas gun. The results show that shell length decreases and the plastic deformation zone diameter increases after impact. Damage deformation degree decreases with increased shell strength, reduced shell and internal charging mass summation and reduced impact velocity square. The model calculated value agrees well with the test data. The deformation model can be used to predict overload damage deformation for such detonator.

Deformation Research of T10 Steel at Low Stress Repeated Impact

2012 ◽  
Vol 487 ◽  
pp. 445-448
Author(s):  
Jiong Jie Wu ◽  
Ge Yan Fu
Keyword(s):  
Heat Treatment ◽  
Plastic Deformation ◽  
Impact Test ◽  
Impact Load ◽  
Research Use ◽  
Repeated Impact ◽  
Metallographic Structure ◽  
Hardness Change

The research use an impact test enginery, choose T10 steel samples, and do a low stress repeated impact collisions experiment. By comparing two kinds of different heat treatment of T10 steel, analyze and research its macro plastic deformation phenomena and plastic accumulation law in low stress repeated collision impact load, and observe its hardness change by hardness microscopicand and its metallographic structure by metallographic microscope to discuss its deformation causes.

A discussion on deformation of solids by the impact of liquids, and its relation to rain damage in aircraft and missiles, to blade erosion in steam turbines, and to cavitation erosion - The erosion of solids by the repeated impact of liquid drops

1966 ◽  
Vol 260 (1110) ◽  
pp. 121-139 ◽  
Keyword(s):  
Cavitation Erosion ◽  
Impact Load ◽  
Steam Turbines ◽  
Repeated Impact ◽  
Ductile Metals ◽  
Liquid Drops ◽  
Liquid Impact ◽  
Erosion Behaviour ◽  
Brittle Polymers ◽  
The Impact

An investigation of the erosion of solids by repeated liquid impact at relatively low velocities has been carried out. The work has shown that even at low velocities compressible behaviour of the liquid is important in determining the impact pressure. An attempt has also been made to determine the distribution of the impact load. The mechanism of erosion in brittle polymers and in ductile metals has been studied. The effect of altering the conditions of impact on the erosion behaviour is described.

Numerical Studies on Dynamic Behavior of Tubular Pipes Under Repeated Impacts

2020 ◽  
Author(s):  
Ling Zhu ◽  
Xiangui Wang ◽  
Kailing Guo ◽  
Bin Ma
Keyword(s):  
Numerical Simulation ◽  
Plastic Deformation ◽  
Dynamic Behavior ◽  
Deformation Energy ◽  
Repeated Impact ◽  
Numerical Studies ◽  
Repeated Impacts ◽  
The Impact ◽  
Local Dent ◽  
Good Agreement

Abstract The tubular pipes of Jacket platform may be frequently subjected to repeated impact loadings from vessels and dropped objects during the operation life, which may lead to serious damages to the platform. In this paper, the numerical studies on dynamic behavior of tubular pipe subjected to repeated impact loadings was performed. The deformation profile and permanent deflection in numerical simulation were compared with those in experiment, and good agreement was achieved. Besides, the mechanism of deformation accumulation and energy absorption were analyzed. Results showed that, the tubular pipe mainly produced transverse expanding and local dent, the global bending was very small. The permanent deflection at the middle of the pipe increased as the impact numbers increased, while the increment decreased. In addition, with the increase of impact number, the elastic deformation energy stored by the tubular pipe increased, and the plastic deformation energy decreased.

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