scholarly journals Two-stage magnetic-elasto-pulse stamping of thin sheet parts

2021 ◽  
Vol 2131 (4) ◽  
pp. 042057
Author(s):  
S Nescoromniy ◽  
E Strizhakov ◽  
D Minko
Keyword(s):  
Static Loading ◽  
Complex Shape ◽  
Static Load ◽  
Thin Sheet ◽  
Relative Deformation ◽  
Capacitive Storage ◽  
Elastic Punch ◽  
The Stability ◽  
Processing Zone ◽  
Forging Force

Abstract The article substantiates the use of preliminary static loading and subsequent forging force when stamping thin sheet parts of complex shape with an elastic punch. The static load provides a relative deformation of the order of 20– 30% in the processing zone, which guarantees the stability of the position of the workpiece during subsequent pulsed loading. This technique is very important in the manufacture of asymmetric parts with a thickness of 0.01 – 0.3 mm. As a result, the accuracy of the products obtained corresponds to the 7th grade.The article provides a schematic diagram and a description of the proposed design of a double-action press, and analyzes the cyclogram of the device.It is recommended to carry out a static load with an electric drive, a pulsed one with a magnetic hammer, which is connected to a generator of impulse currents with a capacitive storage with an energy capacity of up to 40 kJ with a natural discharge frequency of the current of 20 kHz.

scholarly journals ANÁLISE DA INTEGRIDADE E DA INSTABILIDADE DINÂMICA DE UM SISTEMA MECÂNICO SUJEITO A BIFURAÇÃO DO TIPO BUTTERFLY

2021 ◽  
Vol 12 (3) ◽  
pp. 14-22
Author(s):  
Michael Dowglas de Gois Silva ◽  
Fábio Roberto Chavarette ◽  
Milton Batista Ferreira Junior ◽  
Rodrigo Francisco Borges Lourenco
Keyword(s):  
Static Load ◽  
Structural Systems ◽  
Spring Stiffness ◽  
Bifurcation Diagrams ◽  
Model Uncertainties ◽  
Geometric Imperfections ◽  
Attraction Basin ◽  
Linear Buckling ◽  
Lower Load ◽  
The Stability

Slender structural systems susceptible to unstable buckling generally losestability at lower load levels than the linear buckling load of the perfect structure. This is mainly due to the geometric imperfections present in real structures. The objective of this work is to determine the integrity measures, together with the stability of the post-critical solutions of a mechanical system subject to unstable symmetrical buckling, Burtterfly-type bifurcation, using a discrete degree of freedom model. Uncertainties in the order of 10% will be considered in its deterministic parameters, to obtain lower and reliable limits for the project. The proposed uncertainty in the spring stiffness parameters does not change the type of bifurcation and the value of the critical load, only the value of the minimum post-critical of the bifurcation diagrams. The results showed the erosion of the attraction basin and the decrease of the factors of integrity, local and global, for the trivial solutions with the increase of the static load, for the investigated bifurcation.

scholarly journals Experimental Study on City Road Collapse under Vibrating Load

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yuxiao Wang ◽  
Gang Shi ◽  
Xiaowei Tian ◽  
Chaoyue Li ◽  
Huanyu Cheng
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Soil Layer ◽  
Formation Time ◽  
Traffic Load ◽  
Scale Model ◽  
The Road ◽  
Ultimate Failure ◽  
The Stability ◽  
Collapse Process

Underground pipeline seepage and traffic load are the important factors causing city road collapse. In this paper, eight groups of indoor scale model experiments are used to study the road collapse caused by pipeline seepage, taking into account the load type, pipeline buried depth, the distance between pipeline and loss channel, the relative position of pipeline and loss channel, and the formation time of loss channel. The results show that when the erosion channel was formed later, the underlying erosion cavity was ellipsoid, while the other erosion cavities were funnel shaped. When only the static load is applied, the time to reach the ultimate failure is longer than that when only dynamic load is applied. The smaller dynamic load can increase the stability of the soil above the seepage pipeline, while the larger dynamic load can accelerate the collapse process. With the formation time of the erosion channel increasing, the erosion void size is larger and the surface is easier to collapse. With the increase of the distance between the loss passage and the pipeline, the damage time of the road surface is also increased. The larger the thickness of the soil layer above the pipeline, the smaller the size of the underground cavity and the surface subsidence.

scholarly journals Snapping of a Planar Elastica With Fixed End Slopes

2008 ◽  
Vol 75 (4) ◽  
Author(s):  
Jen-San Chen ◽  
Yong-Zhi Lin
Keyword(s):  
Theoretical Prediction ◽  
Static Load ◽  
Natural Frequencies ◽  
Equilibrium Configuration ◽  
The Other ◽  
Deflection Curve ◽  
Slope Difference ◽  
The Stability ◽  
Fixed End ◽  
Load Deflection Curve

In this paper, we study the deformation and stability of a planar elastica. One end of the elastica is clamped and fixed in space. The other end of the elastica is also clamped, but the clamp itself is allowed to slide along a linear track with a slope different from that of the fixed clamp. The elastica deforms after it is subjected to an external pushing force on the moving clamp. It is observed that when the pushing force reaches a critical value, snapping may occur as the elastica jumps from one configuration to another remotely away from the original one. In the theoretical investigation, we calculate the static load-deflection curve for a specified slope difference between the fixed clamp and the moving clamp. To study the stability of the equilibrium configuration, we superpose the equilibrium configuration with a small perturbation and calculate the natural frequencies of the deformed elastica. An experimental setup is designed to measure the load-deflection curve and the natural frequencies of the elastica. The measured load-deflection relation agrees with the theoretical prediction very well. On the other hand, the measured natural frequencies do not agree very well with the theoretical prediction, unless the mass of the moving clamp is taken into account.

Dynamic Stability of the Rotating Shaft Made of Boltzmann Viscoelastic Solid

1986 ◽  
Vol 53 (2) ◽  
pp. 424-429 ◽  
Author(s):  
W. Zhang ◽  
F. H. Ling
Keyword(s):  
Dynamic Stability ◽  
High Speed ◽  
Static Load ◽  
Viscoelastic Solid ◽  
Rotating Shaft ◽  
Special Cases ◽  
Analytical Formulas ◽  
Rotating Shafts ◽  
The Stability ◽  
Inclined Angle

A general theory is developed in this paper for studying the dynamic stability of high-speed nonuniform rotating shafts made of a Boltzmann viscoelastic solid. The equation of motion of the shaft is deduced. The stability criteria are derived by using this equation. The unstable regions for a nonhomogeneous viscoelastic shaft are worked out numerically. Analytical formulas are also given in this paper for determining the planar deflection of the shaft and its inclined angle due to a planar static load. The conclusions for special cases given in the literature known to the authors are all covered by the results in this paper.

scholarly journals Study the Behaviour of Underground Oil Cavern Under Static Loading Condition

2021 ◽  
Author(s):  
Ritesh D Lokhande ◽  
Krishna Chimmani Vamsi
Keyword(s):  
Crude Oil ◽  
Static Loading ◽  
Loading Condition ◽  
Underground Structures ◽  
Technical Data ◽  
Oil Reserves ◽  
Underground Cavern ◽  
2D Modelling ◽  
Natural Oil ◽  
The Stability

Abstract The country population is increasing rapidly and the needs to make lives easier daily. Some of the essential needs for this generation are crude oil and electricity. India unfortunately does not possess any oil reserves to meet the needs of the country’s demands. So, India is importing oil from other countries. Whenever there are situations like war, pandemic (COVID-19) and other emergencies, the natural oil reserved countries cannot export the oil to other countries which will lead to great chaos in the country. To avoid this situation storing the crude oil is necessary. Building surface giant structures for storing the oil is difficult and won’t be economical. So, India is constructing giant underground structures called caverns, which will reserve the oil. The present study is focused on the stability of the underground cavern structure and understanding the importance of water curtaining system. To analyze the stresses and displacement 2D modelling has been done. In this, wet and dry models are prepared and analysed based on the available geological and geo-technical data to determine the stresses around the cavern and the displacement which will reach on surface due to excavation.

The Influence of Structure-Forming Factors on the Properties of Polymer Composite Material under Static Loading

2018 ◽  
Vol 284 ◽  
pp. 163-166
Author(s):  
A.O. Korneeva ◽  
R.Yu. Saprykin ◽  
A.B. Bondarev
Keyword(s):  
Composite Material ◽  
Polymer Composite ◽  
Static Loading ◽  
Static Load ◽  
Polymer Composite Material ◽  
Bonding Layer ◽  
Spreading Factor ◽  
Elastoplastic Properties ◽  
Cyclic Durability ◽  
Polymer Component

The peculiarities of influence of static load on strength characteristics of polymer concretes based on furfural acetone monomer (FAM) are considered in the article. Resistance of static load fatigue is an independent strength characteristic, which should enter into the practice of mechanical testing of materials possessing elastoplastic properties. The regression equation has been obtained as a result of the experiment on a polymer composite material (PCM), which allowed constructing the response surface of the static loading of the polymer composite material based on the resin FAM. A second-order plan for three factors studying static load of a tested composite material is also presented in the paper. It has been established that the ratio of the polymer component to the filler spreading factor is the fundamental ideas influencing the cyclic durability of polymer concretes, while the thickness of the polymer bonding layer and the coarse aggregate are an insignificant factor.

scholarly journals Viscous Potential Flow Analysis of Electroaerodynamic Instability of a Liquid Sheet Sprayed with an Air Stream

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Mukesh Kumar Awasthi ◽  
Vineet K. Srivastava ◽  
M. Tamsir
Keyword(s):  
Electric Field ◽  
Potential Flow ◽  
Thin Sheet ◽  
Flow Analysis ◽  
Liquid Sheet ◽  
Liquid Stream ◽  
Viscous Potential Flow ◽  
Two Fluids ◽  
Air Stream ◽  
The Stability

The instability of a thin sheet of viscous and dielectric liquid moving in the same direction as an air stream in the presence of a uniform horizontal electric field has been carried out using viscous potential flow theory. It is observed that aerodynamic-enhanced instability occurs if the Weber number is much less than a critical value related to the ratio of the air and liquid stream velocities, viscosity ratio of two fluids, the electric field, and the dielectric constant values. Liquid viscosity has stabilizing effect in the stability analysis, while air viscosity has destabilizing effect.

ESTIMATION OF STABILITY OF LATERAL ROCKS IN A COAL MASSIF WITH INTRODUCE DEFORMATION CHARACTERISTICS OF PROTECTIVE CONSTRUCTIONS

2021 ◽  
pp. 64-74
Author(s):  
Leonid Bachurin ◽  
◽  
Ihor Iordanov ◽  
Olha Kohtieva ◽  
Vitaliy Dovgal ◽  
...  
Keyword(s):  
Uniaxial Compression ◽  
Deformation Modulus ◽  
Bending Stiffness ◽  
Practical Significance ◽  
Relative Deformation ◽  
Deformation Characteristics ◽  
Protective Structure ◽  
The Stability ◽  
Protective Structures ◽  
Supporting Structures

Purpose. Evaluate the stability of lateral rocks in the coal massif containing the workings, with introduce count the deformation characteristics of security structures. Methods. To achieve this goal, laboratory studies of the deformation characteristics of security structures located between the simulated roof and the sole of the coal seam, which were subjected to uniaxial compression. Results. It is proved that the deformation characteristics of protective structures affect the stability of lateral rocks in the coal massif containing the workings. The nature of the deformation of security structures under the action of external forces is determined by their rigidity. All other things being equal, when the roof and sole rocks have a constant bending stiffness, their stability depends on the rigidity of the supporting structures and the direction of the load applied in the tangential (wooden cogs, rolling cogs) or radial (riser bushes) direction. For the simulated security structures with an increase in the compressive load, a simultaneous linear increase in their stiffness and deformation modulus is recorded. Moreover, for wooden pillars, when the load is applied across the fibers, the clamped struts of wooden structures are compacted, as a result of which the convergence of the lateral rocks is limited. There is no such pattern for rigid structures in the form of bushes made of wooden risers. After the loss of stability of the protective structure, the modulus of deformation decreases, which is accompanied by an increase in the convergence of the side rocks to the complete destruction of the structure. It is recommended to abandon the rigid and at the same time fragile protective structures designed to support the side rocks. Scientific novelty. The stability of the roof in the carbonaceous massif containing the workings is estimated by the maximum relative deformation of the supporting structures as a result of uniaxial compression using a coefficient characterizing the ratio of the rigidity of the working protective structure and bending stiffness of the side rocks. Practical significance. To ensure the stability of the side rocks in the coal massif and the operational condition of the workings adjacent to the clearing face at the extraction site of the coal mine, it is necessary to focus on the use of flexible structures.

scholarly journals Numerical Analysis of Roadway Rock-Burst Hazard Under Superposed Dynamic and Static Loads

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3761 ◽  
Author(s):  
Kong ◽  
Jiang ◽  
Jiang ◽  
Wu ◽  
Chen ◽  
...  
Keyword(s):  
Energy Density ◽  
Rock Burst ◽  
Elastic Energy ◽  
Dynamic Load ◽  
Static Loading ◽  
Static Load ◽  
Dynamic Loads ◽  
Loading Conditions ◽  
Static Loads ◽  
Elastic Energy Density

Microseismic events commonly occur during the excavation of long wall panels and often cause rock-burst accidents when the roadway is influenced by dynamic loads. In this paper, the Fast Lagrangian Analysis of Continua in 3-Dimensions (FLAC3D) software is used to study the deformation and rock-burst potential of roadways under different dynamic and static loads. The results show that the larger the dynamic load is, the greater the increase in the deformation of the roadway under the same static loading conditions. A roadway under a high static load is more susceptible to deformation and instability when affected by dynamic loads. Under different static loading conditions, the dynamic responses of the roadway abutment stress distribution are different. When the roadway is shallow buried and the dynamic load is small, the stress and elastic energy density of the coal body in the area of the peak abutment stress after the dynamic load are greater than the static calculations. The dynamic load provides energy storage for the coal body in the area of the peak abutment stress. When the roadway is deep, a small dynamic load can still cause the stress in the coal body and the elastic energy density to decrease in the area of the peak abutment stress, and a rock-burst is more likely to occur in a deep mine roadway with a combination of a high static load and a weak dynamic load. When the dynamic load is large, the peak abutment stress decreases greatly after the dynamic loading, and under the same dynamic loading conditions, the greater the depth the roadway is, the greater the elastic energy released by the dynamic load. Control measures are discussed for different dynamic and static load sources of rock-burst accidents. The results provide a reference for the control of rock-burst disasters under dynamic loads.

The Stability Analysis on the Different Types of Single Layer Latticed Shell

2013 ◽  
Vol 788 ◽  
pp. 598-601
Author(s):  
Jun Qiang Wu ◽  
Yu Cui
Keyword(s):  
Stability Analysis ◽  
Static Load ◽  
Single Layer ◽  
Static Stability ◽  
Different Types ◽  
Practical Engineering ◽  
Small Structure ◽  
The Stability ◽  
Lattice Shell ◽  
Better Than

This single-layer spherical reticulated shell has the advantages of reasonable stress,beautiful appearance ,fast construction,is widely applied in practical engineering. Through the static stability analysis of three kinds of single-layer spherical lattice shell structure using ansys, we get them in the uniform deformation under static load, the modal, buckling load. The results show that: The Kiewitt latticed shells displacement is small, structure is stable, better than SchwedLer and lianfang.

Sign in / Sign up

Export Citation Format

Share Document