浅谈冲压修边模结构及常见问题解析

通过现场修边模具调试,对模具调试常见问题,即毛刺、制件变形、废料不下滑等问题进行研究,分析问题产生原因,提出整改对策。

Elastoplastic model for discontinuous shear deformation of deep rock mass

Deep rock mass possesses some unusual properties due to high earth stress,which further result in new problems that have not been well understood and explained up to date.In order to investigate the deformation mechanism,the complete deformation process of deep rock mass,with a great emphasis on local shear deformation stage,was analyzed in detail.The quasi continuous shear deformation of the deep rock mass is described by a combination of smooth functions:the averaged distribution of the original deformation field,and the local discontinuities along the slip lines.Hence,an elasto-plastic model is established for the shear deformation process,in which the rotational displacement is taken into account as well as the translational component.Numerical analysis method was developed for case study.Deformation process of a tunnel under high earth stress was investigated for verification.

Influence of variables in deep drawing of AA 6061 sheet

Deep drawing is one of the most important processes for forming sheet metal parts.It is widely used for mass production of cup shapes in automobile,aerospace and packaging industries.Cup drawing,besides its importance as forming process,also serves as a basic test for the sheet metal formability.The effect of equipment and tooling parameters results in complex deformation mechanism.Existence of thickness variation in the formed part may cause stress concentration and may lead to acceleration of damage.Using TAGUCHI's signal-to-noise ratio,it is determined that the die shoulder radius has major influence followed by blank holder force and punch nose radius on the thickness distribution of the deep drawn cup of AA 6061 sheet.The optimum levels of the above three factors,for the most even wall thickness distribution,are found to be punch nose radius of 3 mm,die shoulder radius of 8 mm and blank holder force of 4 kN.

Deformation and Failure Mechanism of Phyllite under the Effects of THM Coupling and Unloading

Although the study of TM(Thermo Mechanics),HM(Hydraulic-Mechanics) and THM(Thermo-Hydraulic-Mechanics) coupling under a loading test have been under development,rock failure analysis under THM coupling and unloading is an emerging topic.Based on a high temperature triaxial unloading seep test for phyllite,this paper discusses the deformation and failure mechanism of phyllites under the "H M,T→H,T→M" incomplete coupling model with unloading conditions.The results indicate that the elastic modulus and initial permeability decrease and the Poisson's ratio increases with increasing temperature;the elastic modulus decreases and the Poisson's ratio and initial permeability increase with increasing water pressure.During the unloading process,rock penetrability is small at the initial elastic deformation phase,but the penetrability increases near the end of the elastic deformation phase;mechanisms involving temperature and water pressure affect penetrability differently.Phyllite failure occurs from the initial thermal damage of the rock materials,splitting and softening(which is caused by pore water pressure),and the pressure difference which is formed from the loading axial pressure and unloading confining pressure.The phyllite failure mechanism is a transtensional(tension-shearing) failure.

The Preparation of Ultra-fine Calcium Carbonate and Its properties Study

This article adopts the double decomposition method, select the appropriate experimental conditions and operation process, respectively add appropriate amount of sodium carboxymethyl cellulose （CMC） as crystal control agent to study the influence of crystalline of ultrafine calcium carbonate. The experimental results show that the different concentrations of CMC as crystal control agent on the morphology and crystal structure of calcium carbonate have obvious effect, which emerge morphology change from square to spherical, crystalline transition from calcite to aragonite. Thus, the results provide experimental data and theoretical basis for the use of different additives, and provide experimental basis and feasible solution for this kind of reaction.

Contact binaries:Ⅱ.The importance of deformation caused by rotation and tides to the light curve of a contact binary

The theoretical light curves of contact binaries are calculated with and without putting in the contact binary evolution model.Firstly,we do not use the contact binary evolution model.A comparison of the light curve is performed with and without the deformation caused by rotation and tides.It shows that the light curve presents many differences,especially on the bottom and top.Secondly,we adopt the contact binary model [Huang R Q,et al.Chin J Astron Astrophys,2007,7:235-244;Song H F,et al.Chin J Astron Astrophys,2007,7:539-550] and compute the theoretical light curve with and without rotational and tidal effects by studying three binary systems(with low-,intermediate-and high-mass components).The bottom and top of the theoretical light curves are discussed and compared to observations.The results show that taking into account the rotational effect has a better agreement with observations than without it.Therefore,the deformation of the light curve of contact binaries caused by rotation and tides is very important.Meanwhile,the rotational and tidal effect can advance the start of the semi-detached,contact phase and the time of mass-reversal.