起皱

It is shown that the distribution of their veins were similar; and both wings tend to be much stiffer under upward loading than under downward loading; the area of a forewing is smaller than that of a hind wing from the same dragonfly; and the structural performance of the forewing is superior to that of the hind wing.

对具有不同起拱、起皱高度的计算模型进行静力分析，发现起拱和起皱的幅度越大，结构的刚度也越大，但单位面积上所用的材料则呈非线性增加，相应地增加了结构自重。

In order to compare the results for the three different die gaps, the ratio of the two principal strains is introduced, being min/max, where max and min are the major and the minor principal strains, respectively. Hosford and Caddell [5] have shown that if the absolute value of is greater than a critical value, wrinkling is supposed to occur, and the larger the absolute value of , the greater is the possibility of wrinkling.

为了比较三种不同模具间隙的结果，两种主要张力的比率被介绍-是最小值/最大值，这里最小值/最大值是主要的和次要的张力，分别的， Hosford and Caddell [5] 显示如果他的绝对值比临界值大，起皱应该会产生，越大的绝对值，则越大的起皱产生。

These two defects were suppressed when polyurethane elastic cushions and steel paddings were used between the titanium alloy retiary sheet and the press punch with the blankholder device in the forming technology mode, and the 3D curved surface of prosthesis with good quality can be acquired.

模拟结果表明：采用前两种成形工艺得到的钛合金颅骨修复体表面出现压痕或起皱缺陷，采用在基本体和钛合金网板之间放置聚氨酯弹性垫和钢质垫板并使用压边圈这种成形工艺时，可以抑制压痕和起皱的产生，获得良好的成形效果。

There are three types of wrinkle which frequently occur in the sheet metal forming process: flange wrinkling, wall wrinkling, and elastic buckling of the undeformed area owing to residual elastic compressive stresses.

在金属板料成型加工中通常存在三种类型的起皱现象：法兰起皱，侧壁起皱，和由于残余压应力在未变形区产生的弹性变形。

In this paper is proposed the recearch of Shear Wrinkling.

本论文在研读文献资料和调查实际中，提出了"剪应力起皱"的研究方向，这一研究对起皱问题的深入探讨和实际问题的解决都将起到一定的推动作用。

Cockling: The puckered effect produced when printing sheets of paper having wavy or tight edges.

起皱：用带有浪形纸边或弓形纸边的纸张施印，起皱情况就会发生。

The state of being crisped or curled.

起 皱，卷曲起皱或卷曲的状态

The act of crisping or curling.

起 皱，卷曲起皱或卷曲的行为

The mechanism of instability wrinkling in the process based on minimum energy principle is revealed, uniform mathematic description of the wrinkling wave on the strip of in-plane bending is established, the internal and external energy is deduced by energy method, and a uniform criteria of internal and external wrinkling is established; then how to combine the criteria with the FEM simulation system to make the numerical prediction of wrinkling into reality is also resolved in the paper. The effects of the forming parameters on the deforming result are analyzed by the uniform predict criteria. The results show as follows: as the compress width increase, external wrinkling first come into being, then internal winkling do, and finally in-plane bend occur; the loading wedge angle increase, internal winkling first come into being, thenin-plane bend do, and finally external wrinkling occur; in-plane bend is possible to occur with a increase of the strain-hardening exponent and the strength coefficient; and the effect of the friction factor may be ignored.

2揭示了板带不均匀压下面内弯曲成形过程基于能量原理的失稳起皱机理，提出了统一的描述内外缘起皱波形的函数，采用变分法推导了服从该波形函数的内外缘起皱能，建立了统一的起皱预测准则；将新建立的统一的起皱预测准则引入到数值模拟系统IBS中，数值预测结果与实验结果的吻合较好；分析了成形过程各参数对起皱的影响规律：随着接触变形区宽度的逐渐增大，先是发生外缘起皱，然后发生内缘起皱，进而才出现稳定成形；随着实际加载楔角的增大，先是发生内缘起皱，然后发生稳定成形，进而出现外缘起皱；硬化指数和强化系数增大，易于稳定成形；摩擦因子对起皱的影响不明显；而且接触变形区宽度对起皱的影响最大。

In addition, the blank holding force that is required to avoid wrinkle and rupture during conical part deep drawing is researched. The necessity of reasonable blank holding force in pressing is expounded. From the view of mechanical analysis, the wrinkle critical condition of side-wall is derived for the first time by the stress state of side-wall, the main deformation region on blank. According to the critical condition of plastic instability for flange, side--wall, corner of punch on blank, The blank holding force in conical part deep drawing is divided into four different regions within its forming figure. The basic principle of reasonable blank holding force during stamping is summarized and provided. The mathematical model of reasonable blank holding force that avoids the wrinkle and rupture is established and verified by the finite element numerical simulation and the grid experiment method. The result shows that it is accurate and reliable.

此外，本文还研究了圆锥形件拉深成形过程中，随着拉深变形过程的进行，毛坯为避免产生起皱、破坏缺陷而对压边力的需求情况，阐明了圆锥形件拉深成形过程中压边力合理变化的必要性；由毛坯主要变形区悬空锥壁部分的受力变形情况，从力学分析的角度，首次推导得出了圆锥形零件悬空锥壁起皱失稳的临界条件；并根据主要变形区法兰、悬空锥壁及凸模圆角部分的塑性失稳临界条件，在其成形范围图中，将圆锥形件成形过程中的压边力划分为四个区域；总结并提出了圆锥形件成形过程中压边力合理变化的基本原则；建立了防止起皱、破坏缺陷产生的压边力合理变化的数学模式，并得到了有限元数值模拟及网格实验法的验证，证实了理论分析结果的正确性和可靠性。

It is also known as one of the most poisonous naturally occurring substances.

它也被称为一个最自然发生的有毒物质。

The greatest stress is found at the location on the cross section where V is the largest.

最大应力出现在横截面上V为最大的地方。