Wide-open V-shaped conjugate strike-slip faults in Asia are typically related to extrusion tectonics. However, the tectonic model based on the slip-line theory of plasticity has some critical problems associated with ...Wide-open V-shaped conjugate strike-slip faults in Asia are typically related to extrusion tectonics. However, the tectonic model based on the slip-line theory of plasticity has some critical problems associated with it. The conjugate sets of slip-lines in plane deformation, according to the theory of plasticity should be normal to each another but, in reality, the angles between the conjugate strike-slip faults, which are regarded as slip-lines in extrusion tectonics in the eastern Mediterranean, Tibet-middle Asia, China and the Indochina Peninsular regions, are always more than 90° （on average -110°） in the direction of contraction. Another problem is that the slip-line theory fails to explain how, in some cases, e.g., in the Anatolian area in the eastern Mediterranean, the extrusion rate is much higher than the indent rate. The two major problems are easy to solve in terms of the Maximum-Effective-Moment （MEM） Criterion that predicts that orientations of the shear zones are theoretically at an angle of 54.7° and practically at angles of 55°± 10° with the σ1- or contractional direction. The orientations of the strike-slip faults that accommodate extrusion tectonics are, therefore, fundamentally controlled by the MEM Criterion. When extrusion is along the MEM-orientations, the extruding rate is normally higher than the indenting rate.展开更多
This paper presents the elastic and plastic deformation of the steel helmet with coldextrusion moulding. The plastic streamline of the plastic mould-making process for ellipse thinplate is described. The distribution ...This paper presents the elastic and plastic deformation of the steel helmet with coldextrusion moulding. The plastic streamline of the plastic mould-making process for ellipse thinplate is described. The distribution of slip-line is established based on the plastic streamline. Theextrusion force of plastic moulding of the steel helmet is calculated by using of slip-line method.Furthermore, an applied example is given.展开更多
采用超声表面滚压(Ultrasonic surface rolling extrusion,USRE)加工方法对调质态40Cr轴进行处理。通过对处理表层进行微观结构观察发现:该加工方法既可以使表层纳米晶粒细化至3～7nm,还可以使表面粗糙度水平降至0.05μm;USRE样品表面...采用超声表面滚压(Ultrasonic surface rolling extrusion,USRE)加工方法对调质态40Cr轴进行处理。通过对处理表层进行微观结构观察发现:该加工方法既可以使表层纳米晶粒细化至3～7nm,还可以使表面粗糙度水平降至0.05μm;USRE样品表面附近区域形成了厚度约为200μm的流变组织,且晶粒尺寸沿厚度方向呈现梯度分布。力学性能测试证明:USRE试件表面显微硬度提高了63%,表面残余应力最高为-846MPa,压缩应力层深度可达1mm以上。摩擦磨损对比试验表明:USRE方法能够降低金属表面摩擦因数,提高其抗磨损性能。展开更多
基金supported by the National Nature Sciences Foundation of China(NNSFC/Grant Nos.90714006 and 40872133)
文摘Wide-open V-shaped conjugate strike-slip faults in Asia are typically related to extrusion tectonics. However, the tectonic model based on the slip-line theory of plasticity has some critical problems associated with it. The conjugate sets of slip-lines in plane deformation, according to the theory of plasticity should be normal to each another but, in reality, the angles between the conjugate strike-slip faults, which are regarded as slip-lines in extrusion tectonics in the eastern Mediterranean, Tibet-middle Asia, China and the Indochina Peninsular regions, are always more than 90° （on average -110°） in the direction of contraction. Another problem is that the slip-line theory fails to explain how, in some cases, e.g., in the Anatolian area in the eastern Mediterranean, the extrusion rate is much higher than the indent rate. The two major problems are easy to solve in terms of the Maximum-Effective-Moment （MEM） Criterion that predicts that orientations of the shear zones are theoretically at an angle of 54.7° and practically at angles of 55°± 10° with the σ1- or contractional direction. The orientations of the strike-slip faults that accommodate extrusion tectonics are, therefore, fundamentally controlled by the MEM Criterion. When extrusion is along the MEM-orientations, the extruding rate is normally higher than the indenting rate.
文摘This paper presents the elastic and plastic deformation of the steel helmet with coldextrusion moulding. The plastic streamline of the plastic mould-making process for ellipse thinplate is described. The distribution of slip-line is established based on the plastic streamline. Theextrusion force of plastic moulding of the steel helmet is calculated by using of slip-line method.Furthermore, an applied example is given.
文摘采用超声表面滚压(Ultrasonic surface rolling extrusion,USRE)加工方法对调质态40Cr轴进行处理。通过对处理表层进行微观结构观察发现:该加工方法既可以使表层纳米晶粒细化至3～7nm,还可以使表面粗糙度水平降至0.05μm;USRE样品表面附近区域形成了厚度约为200μm的流变组织,且晶粒尺寸沿厚度方向呈现梯度分布。力学性能测试证明:USRE试件表面显微硬度提高了63%,表面残余应力最高为-846MPa,压缩应力层深度可达1mm以上。摩擦磨损对比试验表明:USRE方法能够降低金属表面摩擦因数,提高其抗磨损性能。
