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Then the factors of hot spots generated in the production of emulsion explosives and the occurred conditions of the heat accumulation are analyzed and summarized.
Physical properties of explosives and chemical composition of the underlying causes detonation turn affect the combustion process, such as the gas product hematocrit, burning heat and mass burn rate, and the quality of the fuel consumption rate is the decisive factor, it depends on the oxygen balance of explosives, permeability and the shape and size of the particles.
Those who can improve the quality of the fuel consumption rate factors can speed up the burning to detonation transition process.
At the same time, the following factors need further study: (A) the main component of explosives as well as the presence of ammonium nitrate product containing impurities, greatly accelerated the thermal decomposition is explosive burning to detonation transition root causes.
Explosives under the physical and chemical properties of the role of non-gaseous products hematocrit detonator explosives, burning heat and mass burn rate of internal combustion to detonation transition

The result shows that the optimized ladder structure has smaller stress and smaller displacement, the mechanical properties are better.
Considering the complexity of the practical ladder structure, there are some simplifications about the model: (1) Omitting the less important components which are not made for ensuring the intensity and stiffness. (2) Without considering the material properties change of weld. (3) Assume the chassis of ladder structure is fixed link. (4) The working platform is equivalent into the ladder structure.
Ladder in work, mainly suffer the structure weight, platform weight and working load (assume the ladder works under ideal condition, not affected by wind).
Such optimization not only improves the whole mechanical properties between the adjacent beams, but also reduces the risk of missing steps by firefighters.
References [1] Li Jinxue, The inspection and maintenance of ladder truck, Special Vehicle, 2002.04 41 43 [2] Zhu Guoqi, An improve proposal about ladder truck which based on the Human Factors Engineering, Ergonomics, 2011.09 49 53 [3] Tang Shanqing, The finite element analysis of ladder truck structure, Products and Technology, 2008.08 87 90

Research on Some Key Mechanical Properties of Silicon Nitride Thin Films Deposited by PECVD Qunfeng Yang1, Jianyi Zheng1, a, Junqing Wang1, Junhui Lin1, Xuenan Zhao1, Gaofeng Zheng1 1Department of Mechanical and Electrical Engineering, Xiamen University, China, 361005 azjy@xmu.edu.cn Keywords: Residual stress, Silicon nitride(SiNx) thin films, PECVD Abstract.
Introduction The SiNx thin film has high chemical stability, good insulation, and excellent mechanical properties[1-3], and thus has been widely used as the support structure of the device in MEMS[4-6].
But some charateristics of the film seriously affected the performance of the thin film.
Conclusions This experiment mainly studied about the key mechanical properties of the SiNx films, including film surface quality, thickness uniformity, and residual stress.
Ishida: IEEE 21st International Conference on Micro Electro Mechanical Systems. (2008), p. 359

Study by [9] Cai et.al focused on the fracturing features Al alloy and the mechanical properties of the alloy was observed.
A study by [10] Wen Cheng et.al saw the Al alloy in a composite with TiB2+TiC and the microstructure and mechanical properties was observed.
Other factors such as pores and un-melted powders may also play a role in lowering the density of the sample 3.
Ibrahim (2016) “The Influence of Selective Laser Melting Parameters on Density and Mechanical Properties of AlSi10Mg”.
Cairney, (2019) “Factors that affect the properties of additively manufactured AlSi10Mg: Porosity versus microstructure”, Additive Manufacturing, Volume 29,2019, 100805. https://doi.org/10.1016/j.addma.2019.100805

Analysis of the microstructure of welded joints, indexes of mechanical properties are provided and failure mechanism in the area of fatigue and static fracture is analyzed.
Welding efficiency and quality depends on many factors and often welded joint strength and longevity vary from designed.
The structures of materials and welds, as well as their mechanical properties, were determined.
Peculiarities of microstructure influence properties of resistance to the cyclic loading.
A particular intermediate area still exists which depends on various factors.

Tensile curves of the material at a room temperature of 400℃ are shown in Fig.1 and the mechanical properties are shown in Table 1.
The crack growth in MSC stage is mainly affected by the structural factors, but the crack growth in PSC stage which is mainly affected by mechanical factors.
The short cracks evolution behavior under the leadership of mechanical factors tends to be regular and simple.
The increase of strain amplitudes will strengthen the effect of mechanical factors, making the crack growth rate more stable and the damage evolution degree more regular.
Strain amplitudes as one of mechanical factors will effect the growth rate of the fractal dimension.

Engineering practice shows that the tunnel large deformation, resulting in harm to a large extent, high processing risk, schedule delays longer, and may even cause major accidents, causing massive property damage and casualties.
The main factors of Xiakou tunnel surrounding rock and supporting structure deformation effects included are:①The geological factors.
The mechanical properties of rock, stability of structural plane and soft matter content of the rock, etc., are the internal factors affecting tunnel in soft rock deformation. ② Engineering disturbance factors.
Before the tunnel excavation, rock in a stable equilibrium state of a three-way force under high geostress environment; After excavation, destruction of rock the original natural state of stress, causing rock stress state redistribution, can lead to stress concentration, external factors of large deformation of surrounding rock. ③ Construction improper factors.
Groundwater and weak rock occurs in water - rock interaction, reducing the mechanical properties of rock, for the rock plastic deformation and expansion deformation provides external conditions, to a certain extent contributed to the effects of high geostress and layered rock on large deformation.

The researches had shown that the protect properties of the ceramic coating to the substrate material were closely related with its structure and phase composition, and essentially were dependent on the electrolyte composition, electrical parameter and other process conditions [4-6], of which voltage parameter was an important factor[7,8].
Discussion The micro-arc oxidation process includes two stages, that is initial oxidation film formation and ceramic coating growth, in which the thermochemistry, electrochemistry and plasmachemistry actions are direct effect factors to formation, growth of coating as well as morphology, structure of coating, just through these factors the voltage parameters affects micro-arc oxidation process.
Matthews “Thickness effects on the mechanical properties of micro-arc discharge oxide coatings on aluminum alloys” Surface and Coatings Technology, Vol.116-119, 1055-1060, September 1999 [3]J.A.
Clyne “Thermo-physical properties of plasma electrolytic oxide coatings on aluminium” Surface and Coatings Technology, Vol.199, Issues 2-3, 22, 168-176, September 2005 [4]V.
Kamyshanskii “Formation of structure and properties of coatings deposited by micro-arc oxidizing on parts fabricated from aluminum alloys” Metal Science and Heat Treatment, Vol.42, Number 10, 411-415, 2000

The mentioned deterioration process affecting blade surfaces of turbine blade rims is analyzed on the basis of continuous monitoring that has been carried out to date.
Thus, the higher mass flow rates for fuel and, consequently, unsigned dimensions of fuel stream leaving the injector nozzle, the more difficult it can be deformed (defected) due to inertia forces, viscosity and other flow-hindering factors that lead to pressure oscillations.
It is one of the factors that have been taken into account so far to decide about further operation of the object that subjects to the wear and tear process.
Strength of material that is used for manufacturing of blades of turbine units for aircraft engines can be determined under the assumption that mechanical properties of the fracture development subjects to linear laws [7-8].
It is why cyclical loads may entail propagation of fissures and cracks at stress factors that are even less than the critical limits, which was already demonstrated in [7-8].

Thermal Mechanical Coupled 3D Finite Element Simulation of Large H-beam in Hot Rolling Process Peiqi Wanga, Qinhe Zhangb*, Baotian Dongc and Rupo Mad School of Mechanical Engineering, Shandong University, Jinan, Shandong, 250061, China alicofer4913@163.com, b*Corresponding Author: zhangqh@sdu.edu.cn, cdongbaotian@sina.cn, dmarp2005@163.com Keywords: Large H-beam, Thermal mechanical coupled, FEM, Re-meshing technique, Hot rolling Abstract.
Introduction H-beam is a kind of efficient economic cross-section profiles with wide flange, thin web, more superior cross-section properties and more reasonable ratio of strength to weight, which is more widely used.
In order to improve the accuracy of simulation, the material is tested by the Gleeble-1500 thermo-mechanical tester to get the true stress-strain data, and then the VUMAT (User-defined Material Mechanical Behavior) programme is written to define material model.
Taking into account the limit of the computer memory and stress property, the mesh is denser in the contact zone between rollers and workpiece based on subdivision method by inserting new points in the model.
The deformation and deflection of roller is an important factor for affecting the accuracy of the shape and dimension of workpiece.