刀具热处理变形量测定及研究

针对原企业标“准产品热处理变形量公差”不能满足生产需要的情况,通过对滚刀、盘类铣刀等刀具热处理后内孔及键槽变形量的测量、跟踪、研究,掌握了现行热处理工艺对不同材料不同类型刀具的影响,并经调整确定了该企业新的《高速钢刀具内孔、键槽热处理变形量标准》,满足了生产需要。

不同方式处理后软土地基侧向变形规律

高速公路建设期侧向位移的控制是评价路基变形的重要依据。依据四川省遂-资(遂宁至资阳)高速公路软基沉降变形观测的数据,通过对现场监测资料的分析,分别探讨西南地区软土路基经塑料排水板(PVD)、碎石桩处理后,路基侧向变形y与深度z,最大侧向变形增量△ym与地表沉降增量△SD,平均侧向变形量Sy与地表沉降量Sf的变化规律。研究表明,(1)根据Boussinesq解答和实测数据得到路堤荷载作用面积下变形y随着深度z大致呈"S"形变化,近地表变化剧烈,随荷载增加最大侧向位移深度基本保持不变,土体最大侧向变形深度与路堤填筑高度无关,与土性有关;(2)经PVD处理后的软基在填筑期、预压期均有大量侧向位移发生,各占总位移量的50%,最大侧向位移深度在距离地表1.0~1.5 m处;(3)经碎石桩处理后软基侧向位移在填筑期已完成总位移量的75%~80%,总位移量明显小于PVD处理后软基侧向位移量,最大侧向位移深度在距离地表2.5~3.5 m处;(4)PVD处理软基在固结阶段△ym/△SD、Sy/Sf分别为0.15~0.30和0.10~0.20,大于填筑前期2~4倍,而碎石桩处理软基固结阶段△ym/△SD、Sy/Sf分别为0.10~0.15和0.03~0.05,各个阶段变化相当。

Ag/Ni20纤维复合材料触点制备过程中的塑性变形

以大变形Ag/Ni20纤维复合材料触点为实验样品,以扫描电镜等为分析手段,根据触点内部纤维组织的变形和分布情况,通过建立5区域应力应变模型,研究大变形金属纤维复合材料触点制备中的塑性问题。结果表明,触点在制备过程中存在压缩和拉伸两种变形,位于钉头与钉角处的第3区和钉头表面的第1区应力应变最集中,为拉伸变形,平均变形量在80%,是裂纹容易产生的地方。材料塑性应满足这两个区域的塑性拉伸变形要求,才能制备出高质量的触点。

Dual mean Minkowski measures of symmetry for convex bodies

We introduce and study a sequence of geometric invariants for convex bodies in finite-dimensional spaces, which is in a sense dual to the sequence of mean Minkowski measures of symmetry proposed by the second author. It turns out that the sequence introduced in this paper shares many nice properties with the sequence of mean Minkowski measures, such as the sub-arithmeticity and the upper-additivity. More meaningfully, it is shown that this new sequence of geometric invariants, in contrast to the sequence of mean Minkowski measures which provides information on the shapes of lower dimensional sections of a convex body, provides information on the shapes of orthogonal projections of a convex body. The relations of these new invariants to the well-known Minkowski measure of asymmetry and their further applications are discussed as well.