Laser-propelling-based method and laser-propelling-based device for producing sheet shock forming limit diagram

Abstract

The invention relates to a method and a device of forming a limit diagram in the technical field of laser shock sheet forming, in particular to a laser-propelling-based method and a laser-propelling-based device for producing a sheet shock forming limit diagram, which are mainly used for judging failure and deformation of sheets such as necking or cracking and for evaluating forming performance of the sheets. The method is characterized in that: a laser controller (2) controls a repeatable frequency pulse laser device (3) to transmit laser beam of a certain laser pulse width, a facular adjusting device adjusts the diameter of a facular, the laser beam acts on a bullet, the bullet produces momentum under the laser effect to act on different sheets with different widths, a bullet guide structure is changed along with different width of the sheets, the bullet guide structure guarantees an acting force and an acting direction of a shock force, so the sheets are uniform to deform; and by changing the length-to-width ratio of the sheets (11), different limit stress points under different stress ratios can be obtained so as to obtain the forming limit diagram of the sheets.

Description

technical field [0001] The invention relates to a method and a device for making a sheet metal forming limit diagram, in particular to a method and a device for making a sheet metal impact forming limit diagram based on laser propulsion. Background technique [0002] Laser shock sheet forming is a composite forming technology that integrates material modification, strengthening and forming. It has the characteristics of ultra-high pressure, fast speed and high strain rate. It has a wide range of potential applications in many fields such as automobiles, aviation and defense industries. prospect. However, the research on laser shock forming has just started, and many problems such as forming fracture have been encountered, and the development of technology has encountered a bottleneck. The forming limit diagram is an important criterion for evaluating the formability of materials, so it is necessary to study and ensure the good formability of sheet metal in high strain rate ...

AI Technical Summary

Problems solved by technology

[0003] When laser shocking sheet metal is formed, often because of the excessive pressure of the shock wave during the impact forming process, it is easy to cause the sheet metal to be broken or deformed such as necking, so it is necessary to explore the forming performance of the sheet metal under laser shock Criterion - laser shock forming limit diagram; the forming limit diagram of laser shock metal sheet cannot be replaced by the forming limit diagram of stamping metal sheet by traditional pressure processing technology, because laser shock sheet forming has ultra-high pressure, fast and high strain The traditional pressure processing technology does not have these characteristics; the laser beam is directly impacted on the metal sheet, the sheet is severely cracked, and there are explosive cracks around it, and the ultimate strain value at the rupture cannot be accurately measured, and laser beam impact The directionality of the sheet metal is not good, it is easy to punch in the wrong direction, and the experimental sheet is wasted, so the forming limit diagram (FLD) obtained is not very accurate, and it cannot accurately predict and control the high strain rate formability of the laser shock sheet.

Domestic Jiangsu University Jiang Yinfang and others applied for the invention patent "Laser Shock Sheet Forming Limit Diagram Production Method and Data Acquisition Device", patent authorization number: 200910264808.X, this patent needs to manufacture elliptical dies with different ellipticities, which is not easy To produce a suitable ellipse, the mold making cost is high, the replacement time is long, and because the laser shock metal sheet forming has a high strain rate, the strain difference in each direction is small, and the difference in the direction of the long and short axes of the ellipse is also small

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