scholarly journals A Control Method of High Impact Energy and Cosimulation in Powder High-Velocity Compaction

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Dongdong You ◽  
Dehui Liu ◽  
Hangjian Guan ◽  
Qingyun Huang ◽  
Zhiyu Xiao ◽  
...  
Keyword(s):  
Impact Energy ◽  
High Velocity ◽  
Mechanical Energy ◽  
High Impact ◽  
Experimental Results ◽  
Hydraulic Control ◽  
Green Density ◽  
High Impact Energy ◽  
High Velocity Compaction ◽  
The Impact

To enhance the impact energy of powder high-velocity compaction (HVC) and thus improve the green density and mechanical properties of the resulting compacts, a mechanical energy storage method using combination disc springs is proposed. The high impact energy is achieved by modifying existing equipment, and the hydraulic control system is developed to implement the automatic control of the energy produced from the disc springs. An interdisciplinary cosimulation platform is established using the ADAMS, AMESim, and LabVIEW software packages to perform the interactive control of the simulation process and the real-time feedback of the simulation results. A mechanical-hydraulic cosimulation of the energy control virtual prototype of the testing machine is conducted using this platform. The influence of the impact energy on the green density is studied according to the HVC experimental results of the iron-based powders, and then, the green compact with the higher relative density is produced. The experimental results indicate that the energy enhancement method using the combination disc springs is reasonable and that the hydraulic control scheme is reliable.

Wear behaviors of WC and TiC on co matrix composites under three-body impact abrasive wear condition

2019 ◽  
Vol 71 (7) ◽  
pp. 893-900 ◽  
Author(s):  
Lei Dong ◽  
Xiaoyu Zhang ◽  
Kun Liu ◽  
Xiaojun Liu ◽  
Ruiming Shi ◽  
...  
Keyword(s):  
Wear Rate ◽  
Abrasive Wear ◽  
Impact Energy ◽  
Wear Behavior ◽  
High Impact ◽  
Impact Wear ◽  
High Impact Energy ◽  
Content Type ◽  
Three Body ◽  
The Impact

Purpose The purpose of this paper is to investigate the tribological properties of the WC/TiC-Co substrate under different loading conditions under three impact abrasive wear conditions. Design/methodology/approach The three body collisional wear behavior of Co alloy with WC and TiC at three impact energy was studied from 1 to 3 J. Meanwhile, the microstructure, hardness, phase transformation and wear behavior of these specimens were investigated by scanning electron microscopy, Rockwell hardness (HRV), EDS and impact wear tester. The resulting wear rate was quantified by electronic balance measurements under different pressures. Findings The specific wear rate increases with the increase of the nonlinearity of the impact energy and the increase in the content of WC or TiC. The effect of TiC on wear rate is greater than that of WC, but the hardness is smaller. The wear characteristics of the samples are mainly characterized by three kinds of behavior, such as cutting wear, abrasive wear and strain fatigue wear. The WC-Co with fewer TiC samples suffered heavier abrasive wear than the more TiC samples under both low and high impact energy and underwent fewer strain fatigue wears under high impact energy. Originality/value The experimental results show that the wear resistance of the Co alloy is improved effectively and the excellent impact wear performance is achieved. The results can be used in cutting tools such as coal mine cutting machines or other fields.

The Role of the Atmosphere on Boron-Activated Sintering of Ferrous Powder Compacts

2018 ◽  
Vol 18 (1) ◽  
pp. 6-20 ◽  
Author(s):  
V. Vassileva ◽  
H. Danninger ◽  
S. Strobl ◽  
Ch. Gierl-Mayer ◽  
R. de Oro Calderon ◽  
...  
Keyword(s):  
Impact Energy ◽  
Hydrogen Atmosphere ◽  
High Impact ◽  
High Impact Energy ◽  
Energy Data ◽  
Transgranular Cleavage ◽  
Powder Compacts ◽  
The Impact ◽  
Considerable Depth

Abstract Boron has been known to activate densification during sintering of ferrous powder compacts, though with risk of embrittlement. In the present study, specimens Fe-B and Fe-C-B prepared from standard atomized iron powder with addition of ferroboron Fe-21%B were sintered in different atmospheres, and the resulting microstructures and properties were studied. It showed that the activating effect of boron is observed during sintering in argon and in hydrogen while sintering in N2 containing atmospheres results in rapid deactivation of boron, through formation of stable BN. In hydrogen atmosphere, surface deboronizing was observed to considerable depth. Ar is chemically inert, but Ar trapped inside closed pores tends to inhibit further densification. The impact energy data indicated that the embrittling effect of boron is enhanced significantly by presence of carbon. In the fracture surfaces, transgranular cleavage fracture can be observed both at very low and high impact energy values.

High Velocity Compaction of 316L Stainless Powder

2010 ◽  
Vol 44-47 ◽  
pp. 2993-2997 ◽  
Author(s):  
Jin Chen ◽  
Zhi Yu Xiao ◽  
Chao Jie Li ◽  
San Cai Deng ◽  
Tung Wai Leo Ngai ◽  
...  
Keyword(s):  
Impact Energy ◽  
High Velocity ◽  
Delay Time ◽  
Green Density ◽  
Single Impact ◽  
Impact Process ◽  
Ejection Force ◽  
High Velocity Compaction ◽  
Total Impact ◽  
Double Impact

High velocity compaction technology was used to press 316L stainless powders. Effects of impact times on stress wave, green density and ejection force were analyzed. It was found that under the same total impact energy, the first loading time and the actuation duration of the second impact in double impact process were longer when compared with single impact process, while the first delay time was shorter. Furthermore, the green density of compacts prepared by double impact was greater than that prepared by single impact, but no obvious variation in maximum ejection force can be observed between single impact and double impact process.

Optimization of Heat Treatment Parameters of Mo-Free High-Cr Cast Iron Mill Balls

2007 ◽  
Vol 26-28 ◽  
pp. 913-916 ◽  
Author(s):  
Sang Mok Lee ◽  
Bong Hwan Kim ◽  
Je Sik Shin ◽  
B.M. Moon
Keyword(s):  
Heat Treatment ◽  
Cast Iron ◽  
Impact Energy ◽  
Treatment Condition ◽  
Heat Treatment Condition ◽  
High Impact ◽  
High Impact Energy ◽  
Surface Method ◽  
Designs Of Experiments ◽  
Proper Balance

A Mo-free high-Cr cast iron with superior impact-wear resistance was tried to develop for mill balls by alloy design and subsequent heat treatment. The Cr/C ratio was varied up to 7.7 in order to minimize and eventually eliminate Mo addition, still ensuring hardenability. For the proper balance between abrasion resistance and toughness, the combined effects of each heat treatment parameters on the mechanical properties were systematically investigated using Taguchi method and response surface method (RSM), well recognized as powerful tools of the designs of experiments (DOE). It was found that hardness and impact energy were mainly affected by tempering and destabilization conditions, respectively. It is noted that high impact energy of 5.2 J/cm2 was obtained without deteriorating hardness (54 HRc) during the verification experiments under the heat treatment condition optimized by the DOE analyses.

Experimental Study on the Response Characteristics of Oilcans under High-Velocity Fragment Impact

2012 ◽  
Vol 510 ◽  
pp. 500-506
Author(s):  
Chang Hai Chen ◽  
Xi Zhu ◽  
Hai Liang Hou ◽  
Li Jun Zhang ◽  
Ting Tang
Keyword(s):  
Experimental Study ◽  
High Velocity ◽  
High Speed ◽  
Room Temperature ◽  
Experimental Results ◽  
Fuel Oil ◽  
High Speed Camera ◽  
Response Characteristics ◽  
Fuel Oils ◽  
The Impact

To explore the deflagration possibility of the warship cabin filled with fuel oil under impact of high-speed fragments in the condition of room temperature, experiments were carried out employing the small aluminium oilcans filled with fuel oil. Response processes of the oilcans were observed with the help of a high-speed camera. The disintegration as well as flying scattering of the oilcans were analyzed. The reasons for atomization of the fuel oils were presented. Finally, the deflagration possibility of warship oil cabin was analyzed. Results show that the pressure inside the oilcan is quite great under the impact of the high-speed fragment, which makes the oilcan disintegration and flying scattering. Simultaneously, fuel oils inside the oilcans are atomized quickly followed by ejected in front and back directions. Under the same condition as in present tests, deflagration will not occur for fuel oils used by warships. Experimental results will provide valuable references for the deflagration analysis of warship fuel oil cabins subjected to the impact of high-velocity fragments.

Development of a Curved Hopkinson Bar for Long Wavelength Impact Events

2011 ◽  
Author(s):  
Glenn E. Vallee ◽  
Micah C. Bowen
Keyword(s):  
Wave Propagation ◽  
Impact Energy ◽  
Hopkinson Bar ◽  
Experimental Results ◽  
Bend Radius ◽  
Impact Pulse ◽  
Long Wavelength ◽  
Bend Angles ◽  
The Impact ◽  
Impact Events

A study of the feasibility of using a curved Hopkinson bar for the measurement of impact load and energy transmission is presented. The length requirements of straight prismatic bars commonly used to measure long wavelength impact events are often prohibitive, and the use of curved bars can result in a significant increase in wavelength capabilities while reducing the overall size of the measurement apparatus. The ABAQUS/Explicit finite element analysis (FEA) program is used to model steel bars of circular cross section bent with various bend radii and at various bend angles ranging from 15 to 180 degrees. A uniform compressive pressure pulse of known amplitude and wavelength is applied to the FEA models and the wave propagation behavior predicted by ABAQUS/Explicit is then compared to the response predicted by the theory of wave propagation in curved bars and experiments performed using curved bars. The numerical results show good agreement with the theoretical and experimental results. Significant distortion of the incident wave as it travels around the bend results in a transmitted pulse that is not characteristic of the input pulse, particularly at larger bend angles and long wavelengths. The energy transmitted around the bend radius contains only a fraction of the initial impact energy due to large reflections that develop at the bend radius, and this loss increases significantly at larger bend angles and smaller bend radii. However, the transmitted energy can be used to predict the incident energy at a variety of bend angles and bend radii. A curved carbon steel Hopkinson bar is fabricated with a bend angle of 180 degrees and instrumented with strain gauges to monitor the wave propagation within the bar at several locations resulting from a compressive impact pulse. The experimental results agree well with the results predicted using explicit dynamic FEA. The results of this study indicate that a curved Hopkinson bar can be used to predict the impact energy applied to the incident end of the bar using the measurement of the energy transmitted around the bend in the bar. The overall length of the curved Hopkinson bar apparatus can be significantly less than a comparable straight bar apparatus.

scholarly journals Structural Behavior of Ferrocement Concrete Plates Subjected to Flexural and Dynamic Loadings

2021 ◽  
pp. 71-84
Author(s):  
Yousry B. I. Shaheen ◽  
Fatma M. Eid ◽  
Omnia Mesalam
Keyword(s):  
Energy Absorption ◽  
Impact Energy ◽  
Ultimate Load ◽  
Test Results ◽  
High Impact Energy ◽  
Absorption Properties ◽  
Steel Mesh ◽  
Dynamic Loadings ◽  
Steel Bars ◽  
The Impact

Ferrocement is one of the structural materials, widely used due to its advantages from its particular behavior such as mechanical properties, and impact strength. This paper deals with the impact studies and energy absorption properties of ferrocement slabs. For these studies, 11 different ferrocement slabs of size 50 mm X 500 mm X 25 mm were cast with alteration in the combinations of mesh layers and test results are analyzed to find the different crack patterns .The test specimens were loaded by 3.10 kg under its height 1.20 m in the center of plates. The ferrocement plates were divided into 4 groups reinforced with steel mesh, steel mesh with steel bars, percentage of rubber and fiber. The impact energy at initial cracking stage and at failure was determined for all the slabs. Results of reinforced ferrocement plates emphasized that increasing the number of the steel mesh layers in the ferrocement forms increases the first cracking load, ultimate load and energy absorption. Using steel bars with steel meshes led to higher energy absorption than that obtained when using mild steel bars only. Using rubber and fiber achieved high impact energy.

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