Linear Shaped Charge Cutting Property and Charge Cutting Mechanism of Mg-Gd-Y-Zn Alloy

The linear shaped charge cutting technology is an effective technology for aircraft separation.It can separate invalid components from aircrafts timely to achieve light-weight.Magnesium alloy is the lightest metal material,and can be used to cast effective light-weight components of an aircraft construction.However,the application study of the linear shaped charge cutting technology on magnesium alloy components is basically blank.In response to the demand for the linear separation of magnesium alloys,the Mg-12Gd-0.5Y-0.4Zn alloy is selected to carry out the target shaped charge cutting test.The effects of the shaped charge line density,cutting thickness,and mechanical properties on the cutting performance of the alloy are studied.The shaped charge cutting mechanism is analyzed through the notch structure.The results show that the linear shaped charge cutting performance is significantly affected by the penetration and the collapse.The higher the linear density is,the stronger the ability of the linear shaped charge cutter is,and the greater the penetration depth is,which is advantageous.However,the target structure will be damaged when it is too large(e.g.,4.5 g·m^(-1)).Within 12 mm,when the cutting thickness of the target increases,the penetration depth increases.The lower the tensile strength is,the greater the penetration depth is,and the more conducive the penetration depth to the shaped charge cutting is.When the elongation(EL)increases to 12%,the collapse of the target is incomplete and the target cannot be separated.When the tensile strength of the Mg-Gd-Y-Zn alloy is less than 350 MPa,the EL is less than 6.5%,the cutting thickness is less than 12 mm,and the linear shaped charge cutting of the magnesium alloy can be achieved stably.

On cutting sequences of the L-shaped translation surface tiled by three squares

We consider a symbolic coding of bi-infinite non periodic geodesics on the L-shaped translation surface tiled by three squares. Each bi-infinite non periodic geodesic is associated with a cutting sequence corresponding to the sequence of labeled saddle connections hit. We prove that there is a relationship between the cutting sequences and the actions of some affine automorphisms of the translation surface. We also get an explicit formula to determine the direction of a bi-infinite non periodic geodesic by using the corresponding cutting sequence.

Experimental Study on Application of Shaped Charge to Rock Materials Cutting

The mechanic affection on the blast holewalls is simply analyzed and cracking propaga-tion caused by shaped charge is explained inthis paper. In the rock materials cutting, pri-