摘要
在曲面板料激光冲击成形时,很难满足每次都能法向垂直冲击,因此非常有必要进行激光斜冲击板料研究。文章采用钕玻璃激光器、脉冲能量约42J、脉冲宽度约23ns、脉冲功率≥1.2×109W、激光以30°斜冲击LD 31(6063)方形板料,冲击后板料最大变形点偏离试样中心3mm。采用X-350A型X射线应力测定仪、侧倾固定Ψ法和交相关法定峰,分别测量了板料沿激光冲击方向、板料空间分布的残余压应力,得出试样正反两面均是压应力,均小于100MPa,由于变形最大点与方形板料顶点连线长度大于垂直于边长方向,且经过变形最大点直线长度,其在厚度方向产生压应力2σ比较大,产生相同变形所需的力较大,所以产生的残余压应力也较大。在变形最大点与板料顶点最短连线之间的板料受到挤压,板料变厚,硬化严重,产生残余应力最大。
Laser shock forming of metal sheet usually effects on the surface of workpiece in normal direction by laser beam, and produces shock wave force, which is vertical to the surface of workpiece. But it is difficult to shock in normal direction during processing on the surface of forming camber, so it needs to study on oblique shock processing. LD31 of square forging aluminum alloy sheet is shocked by Nd-glass laser in the paper, and is under the function of pulse energy 42J, pulse width 23ns, pulse power 1.2）4109W, the angle of input beam and sample normal is 30°. The center of the deformation of the sheet is 3mm away from the geometric center. Residual stresses of getting across center side length direction and the distribution of space in the positive and negative sides are measured by XRD, all are less than 100MPa. Length of the diagonal of sheet is longer than the one of getting across center side length direction, but the compressive stress a2 in depth along the diagonal is bigger. Because of the bigger compressive stress δ2 in depth of the diagonal, to make the equal formation of the sheet in the diagonal side than the one of getting across center side length direction, the force that needed to make formation in the diagonal is bigger, so the compressive is much bigger. The sheet along the shorter length of the distance between the biggest formation point on the sheet and the capstone of the square sheet is squeezed, then depth enhances, the procession is seriously boosted up, so the compressive stress is the biggest one.
出处
《塑性工程学报》
EI
CAS
CSCD
北大核心
2006年第6期66-69,共4页
Journal of Plasticity Engineering
基金
国家自然科学基金(50275068)
国家863计划(2002AA421120
2002AA336030)
江苏省高校自然科学指导性计划项目(05KJD460045)
关键词
激光斜冲击
冲击成形
残余应力
空间分布
laser shock in oblique angle shock forming residual stress space distribution
