Parameters Varation of Electronic Components in Fuze under High Stress Fields

2010 ◽  
Vol 34-35 ◽  
pp. 1328-1332
Author(s):  
Bo Li ◽  
Hong Xiang Zhang ◽  
Ya Zhang
Keyword(s):  
High Temperature ◽  
Mechanical Stress ◽  
Dynamic Testing ◽  
Carbon Film ◽  
High Stress ◽  
Reference Value ◽  
Stress Fields ◽  
Test Scheme ◽  
Small Range ◽  
High Mechanical Stress

Dynamic testing experiments and test scheme are carried out to testing the parameter varation of typical carbon film resistors and ceramic capacitors of Fuze under high stress fields—high temperature and high mechanical stress overloading, and the changing law of the components parameter are got in high stress fields, then parameter of components instant instable motion under high mechanical stress overloading is discussed by analyzing experimental results, and found out parameters approximate linear in small range in 25°C～125°C, of nonlinear in large range in the very high temperature of 125°C～350°C conditions, which can offer some reference value to prolong lifetime of military electron device.

Crystallization sequence of an A1N-Y2O3-SiO2 glass-ceramic

1986 ◽  
Vol 44 ◽  
pp. 446-447
Author(s):  
T.R. Dinger ◽  
G. Thomas
Keyword(s):  
High Temperature ◽  
Glass Ceramic ◽  
Crystallization Behavior ◽  
High Stress ◽  
Crystallization Sequence ◽  
Sio2 Glass ◽  
Structural Applications ◽  
Ceramic Precursors

The use of Si3N4, alloys for high temperature, high stress structural applications has prompted numerous studies of the oxynitride glasses which exist as intergranular phases in their microstructures. Oxynitride glasses have been investigated recently in their bulk form in order to understand their crystallization behavior for subsequent Si3N4 applications and to investigate their worth as glass-ceramic precursors. This research investigates the crystallization sequence of a glass having a normalized composition of Y26Si30Al11 ON11 and lying in the A1N-Y2O3-SiO2 section of the Y-Si-Al-O-N system. Such glasses exist as intergranular phases in the technologically important Y2O3/Al2O3-fluxed Si3N4 alloys.

Effect of Carbide Content on Temper Embrittlement of 2.25Cr1Mo Steel

2016 ◽  
Author(s):  
Yian Wang ◽  
Guoshan Xie ◽  
Zheng Zhang ◽  
Xiaolong Qian ◽  
Yufeng Zhou ◽  
...  
Keyword(s):  
High Temperature ◽  
Pressure Vessel ◽  
High Stress ◽  
Temper Embrittlement ◽  
Damage Mechanism ◽  
Pressure Vessels ◽  
Nondestructive Method ◽  
Operating Conditions ◽  
Low Alloy Steels ◽  
Carbide Content

Temper embrittlement is a common damage mechanism of pressure vessels in the chemical and petrochemical industry serviced in high temperature, which results in the reduction of roughness due to metallurgical change in some low alloy steels. Pressure vessels that are temper embrittled may be susceptible to brittle fracture under certain operating conditions which cause high stress by thermal gradients, e.g., during start-up and shutdown. 2.25Cr1-Mo steel is widely used to make hydrogenation reactor due to its superior combination of high mechanical strength, good weldability, excellent high temperature hydrogen attack (HTHA) and oxidation-resistance. However, 2.25Cr-1Mo steel is particularly susceptible to temper embrittlement. In this paper, the effect of carbide on temper embrittlement of 2.25Cr-1Mo steel was investigated. Mechanical properties and the ductile-brittle transition temperature (DBTT) of 2.25Cr-1Mo steel were measured by tensile test and impact test. The tests were performed at two positions (base metal and weld metal) and three states (original, step cooling treated and in-service for a hundred thousand hours). The content and distribution of carbides were analyzed by scanning electron microscope (SEM). The content of Cr and Mo elements in carbide was measured by energy dispersive X-ray analysis (EDS). The results showed that the embrittlement could increase the strength and reduce the plasticity. Higher carbide contents appear to be responsible for the higher DBTT. The in-service 2.25Cr-1Mo steel showed the highest DBTT and carbide content, followed by step cooling treated 2.25Cr-1Mo steel, while the as-received 2.25Cr-1Mo steel has the minimum DBTT and carbide content. At the same time, the Cr and Mo contents in carbide increased with the increasing of DBTT. It is well known that the specimen analyzed by SEM is very small in size, sampling SEM specimen is convenient and nondestructive to pressure vessel. Therefore, the relationship between DBTT and the content of carbide offers a feasible nondestructive method for quantitative measuring the temper embrittlement of 2.25Cr-1Mo steel pressure vessel.

The effect of high-temperature and high-stress martensite aging on martensitic transformation and microstructure of Ti–51.5 at % Ni single crystals

2020 ◽  
Author(s):  
E. E. Timofeeva ◽  
E. Yu. Panchenko ◽  
A. S. Eftifeeva ◽  
E. I. Yanushonite ◽  
M. V. Zherdeva ◽  
...  
Keyword(s):  
High Temperature ◽  
Martensitic Transformation ◽  
Single Crystals ◽  
High Stress

A Study on the Lower Flanges Fracture of Endplate Bolted Connection

2006 ◽  
Vol 326-328 ◽  
pp. 983-986
Author(s):  
Hong Wei Ma ◽  
Chong Du Cho ◽  
Qiang Pan ◽  
Hyeon Gyu Beom
Keyword(s):  
Crack Length ◽  
High Stress ◽  
Transverse Load ◽  
Stress Fields ◽  
Finite Element Models ◽  
J Integral ◽  
Bolted Connection ◽  
Static Tests ◽  
Opening Mode ◽  
Set Up

The quasi-static tests on the endplate bolted connections of the new structure system consisting of SCC beam and CCSHRC column are briefly introduced in this paper. Meanwhile, the 3-D solid finite element models of the connections with pre-existing cracks in the lower flange’s high stress fields are set up by ANSYS. The material nonlinearities of concrete, steel and bars, together with the contact between the endplate and column surface are all considered in the model. With the transverse load applied on top of columns, the fracture parameters are calculated by APDL. The results indicate that the opening mode crack will happen mainly. When the pre-existing crack length is 2.50mm and the inter-storey drift is less than 6mm, the stress intensity factor values agree well with the converting values derived from J-integral and the crack tip fields are in elastic state. The J values are highly influenced by the pre-existing crack length, while seldom influenced by the concrete compression strength. Moreover, the J-integral have the trend to sharply increase when the pre-existing crack length is larger than 0.61mm, and the pre-existing crack will grow during loading when its length is larger than 1.35mm.

scholarly journals Development of gear dynamic performance testing machine

2021 ◽  
Vol 12 ◽  
pp. 20
Author(s):  
Ke Li ◽  
Bo Yu ◽  
Zhaoyao Shi ◽  
Zanhui Shu ◽  
Rui Li
Keyword(s):  
High Speed ◽  
Performance Test ◽  
Dynamic Testing ◽  
Mechanical Design ◽  
Dynamic Performance ◽  
External Disturbance ◽  
Testing Machine ◽  
High Stress ◽  
Performance Testing ◽  
Current Application

With the development of gears towards high temperature, high pressure, high speed and high stress, gear measurement, in which only the static geometric accuracy is considered, is unable to meet the current application requirements. While, the low precision and single function gear tester constrains the measurement of gear dynamic performance. For the resolution of this problem, based on the principle of gear system dynamics and several precision mechanical design techniques, a gear dynamic testing machine has been developed, providing new instruments for gear testing. On the basis of research of the principle of dynamic performance test, the primary measurement items of the testing machine have been determined. The measuring principles of each item and the driving and loading form of the testing machine have been examined. The measurement and control system of the testing machine and its corresponding software have been developed. The instrument can not only obtain the static precision index of the gear, but also obtain the dynamic performance index of the gear in variable working conditions. According to the actual test, the uncertainty of instrument is 3.8 μm and the external disturbance caused by the shaft vibration is less than 0.6 μm, which can meet the 5–6 grade precision gear testing requirement.

Reinforcement Calculated Method Based on Disease Model of DongFu Bridge

2012 ◽  
Vol 178-181 ◽  
pp. 2199-2203
Author(s):  
Peng Jun Liu
Keyword(s):  
Finite Element Method ◽  
Dynamic Testing ◽  
Disease Model ◽  
Reference Value ◽  
Original Structure ◽  
Structure Model ◽  
The Finite Element Method ◽  
Stiffness Reduction ◽  
Shear Area ◽  
Main Bridge

On the basis of the static and dynamic testing of the bridge, the original structure model and the model based on stiffness reduction of Dongfu Bridge were analyzed and calculated with the finite element method. The main problem that the anti-shear area of the section in the middle pivot position is not enough is found. On the basis of combination of the passive and active reinforcement styles, a reasonable and feasible reinforcement plan on the girder beam of the main bridge is raised. These conclusions have an important reference value on the bridge reinforcement.

Structural Stability of Nanocrystalline NiAl

1998 ◽  
Vol 4 (S2) ◽  
pp. 720-721
Author(s):  
T. Chen ◽  
J.M. Hampikian ◽  
N.N. Thadhani ◽  
Z.L. Wang
Keyword(s):  
High Temperature ◽  
Structural Stability ◽  
Carbon Film ◽  
Ion Milling ◽  
Plate Impact ◽  
High Melting Point ◽  
Temperature Oxidation ◽  
Transmission Electron ◽  
High Temperature Structural Material

NiAl is an important high temperature structural material, with a high melting point (1640°C), low density and excellent high temperature oxidation resistance. The room temperature ductility of NiAl may potentially be improved with the use of nanocrystalline grain size. However, a key question concerning the application of nanostructured NiAl is about its structural stability at high temperature. The current study is thus focused on the investigation of the structural stability of nanocrystalline NiAl using in-situ transmission electron microscopy (TEM) and differential thermal analysis (DTA).Nanocrystalline B2-NiAl was prepared by ball milling (24 hrs) from elemental Ni and Al powders. Subsequent consolidation into bulk form was performed using dynamic consolidation employing a 3-capsule plate-impact fixture at approximately 400 m/s [1-3]. Powder nanocrystalline NiAl was dispersed on a holey carbon film for TEM observation. TEM specimens of shock compacted bulk NiAl nanocrystals were prepared by cutting, polishing, dimpling and ion milling.

Improving the Quality of a Heteroepitaxial CaF2 Overlayer by Rapid Post Annealing

1984 ◽  
Vol 35 ◽  
Author(s):  
Loren Pfeiffer ◽  
Julia M. Phillips ◽  
T.P. Smith ◽  
W. M. Augustyniak ◽  
K. W. West
Keyword(s):  
High Temperature ◽  
Molecular Beam Epitaxy ◽  
Mechanical Stress ◽  
Short Duration ◽  
Chemical Etching ◽  
Molecular Beam ◽  
Dielectric Breakdown ◽  
Post Annealing ◽  
Random Direction

ABSTRACTWe show that post anneals of short duration at high temperature can markedly improve the quality of CaF2 films grown by molecular beam epitaxy (MBE) on Si (100). Anneals at 1100°C for 20 sec in an Ar ambient improved χmin, the ratio of backscattered 1.8 MeV He4 ions in the aligned to random direction, from as-grown values of .07 to .26, to post post-anneal values of .03 to .045. This is the best χmin yet reported for the CaF2:Si system. The post-annealed films also show improved resistance to chemical etching and mechanical stress, and increased dielectric breakdown voltages.

Study on the Run-in Process between the Contact Line and Saddle of High-Speed Rail

2013 ◽  
Vol 800 ◽  
pp. 317-320
Author(s):  
Lian Mei Song ◽  
Li Xiao Jia
Keyword(s):  
High Temperature ◽  
Contact Line ◽  
Friction Surface ◽  
High Speed ◽  
Carbon Film ◽  
High Speed Rail ◽  
Slide Surface ◽  
Wear And Friction ◽  
Oxidation Damage ◽  
Theory Calculation

At present the wear and friction of pantograph-contact line is studied widely, while the research of the run-in process is little. In the paper they are obtained that the contact area is 0.96mm2, contact stress is 73MPa, current density is 520A/mm2, the contact resistance is 0.01583 and the contact temperature is 2797K on the surface of slide during the run-in period by the theory calculation. The high temperature of slide surface leads to the oxidation damage. While the carbon film comes into being and the friction surface is tending towards stability.

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