共查询到16条相似文献,搜索用时 171 毫秒
1.
以聚丙烯(PP)为薄膜材料,对鼠标外壳进行模外装饰(Out side Mold Decoration,OMD)贴膜,采用有限元方法对该成型过程进行模拟仿真,获得了薄膜厚度的分布及其在X、Y方向变形分布,分析了影响薄膜成型的工艺参数,以成型后薄膜厚度平均值的标准偏差及其在X、Y方向变形量的标准偏差同时最小为目标,采用试验设计(DOE)中的正交数组法对其各项工艺参数进行优化分析,得到了最优的工艺参数,达到了薄膜厚度分布更均匀和其变形精度更高的目的。 相似文献
2.
3.
采用聚丙烯(PP)薄膜对鼠标外壳进行模外装饰贴膜,采用有限元方法对该成型过程进行模拟仿真,获得了薄膜厚度的分布、应力分布及其在x、y方向变形分布,并对其工艺参数的选择作了分析。采用不同的工艺参数模拟该成型过程,重点研究了不同的应变速率对最终成型的影响。结果表明,当应变速率增大时,薄膜的厚度和应力值也随之增大,对在x、y方向上变形影响较小,并且不同的加载方式对成型效果影响比较大。 相似文献
4.
采用FORTRAN语言设计编写DSGZ黏弹性本构模型的材料子程序嵌入至ABAQUS软件中,然后基于模外装饰工艺原理,对六个鼠标外壳贴膜工艺成进行模拟计算,成型后薄膜的最薄厚度为0.183 mm,薄膜在X方向最大变形量为7.417 mm,薄膜在Y方向最大变形量为4.107 mm。通过增大鼠标之间的左右距离同时减小鼠标之间的前后距离,改进之后薄膜的最小厚度为0.184 3 mm,薄膜在X,Y方向上的最大变形量分别为7.104,2.574 mm,其较改进前分别减少了4.22%,37.3%。 相似文献
5.
6.
7.
针对具有复杂形面特征的塑件在成型过程中容易出现翘曲变形的缺陷,以某实际注塑产品翘曲变形量超差为案例,采用计算机辅助工程(CAE)分析平台,对其进行成型过程的数值计算与模拟。以模拟结果为依据,进行合理分析,提出符合实际生产过程的模具结构优化方案。实践表明,利用优化方案进行成型生产,产品翘曲变形超差发生处的x、z方向上最大翘曲变形量由优化前的0.1726、0.1622 mm分别降低为0.0488、0.1156 mm,达到了翘曲变形量应控制在±0.15 mm的要求,得到了符合品质要求的塑件,从而进一步说明CAE技术在工艺优化与模具设计等方面的可靠性与实用性。 相似文献
8.
9.
10.
11.
薄膜蒸发器温度场及膜内给热系数的数值模拟 总被引:2,自引:0,他引:2
应用CFD软件CFX4.4建立了薄膜蒸发器内水及粘性料液的传热计算模型,获得了沿轴向及膜厚方向的液膜平均温度分布,计算了各参数下加热段液膜内给热系数a. 结果表明,进料量及搅拌转速对各料液液膜温度分布及膜内给热系数影响显著. 不同粘度料液在不同操作条件下均存在同一最佳进料量,此时圈形波内截面平均速度 达到最大值, 相应的膜内给热系数a也达到最大值. 高转速或最佳进料量下,纯物质水流动边界层与膜厚之比及温度边界层与膜厚之比均最小,流动边界层与温度边界层存在内在联系. 传递边界层厚度严重影响液膜内温度分布及给热系数. 本研究各工况下,粘性料液尚未形成明显的温度边界层. 相似文献
12.
The stability of film boiling on a vertical, constant temperature wall is analyzed by a steady-state small perturbation method. It was found that large amplifications of the perturbations in the downstream direction are predicted when the vapor Reynolds number falls below a critical value, indicating a great tendency to collapse the vapor film. Using a relatively simple model for the film thickness, the minimum wall temperature required to sustain the vapor film is calculated. The results show a tendency which is in agreement with experimental observation. It is suggested, however, that using a more accurate model for the film thickness can lead to a good prediction of the minimum wall temperature and explain the large effect of liquid subcooling, system pressure, surface tension and other fluid properties. 相似文献
13.
14.
A new dielectric elastomer (DE) film, which was able to show anisotropic large plane deformation actuated by an external electric field, was designed and synthesized. Specifically, an asymmetric di-vinyl monomer cyclohex-3-enylmethyl acrylate (CEA) was incorporated into the middle block of poly(styrene-b-butyl acrylate-b-styrene) as potential crosslinking points. By widely used UV curing technique through a mask, the DE films could be locally hardened any area one selected. This could break the symmetry of the actuation deformation on the DE film plane, maximizing the deformation in a given direction while the actuation area strain remained unchanged. The actuation strainy/strainx reached 2.3, strain in x direction was 10.3% while in y direction was 23%, when the DE film of S(BA-ran-CEA)S with 2.5 mol % CEA incorporated was locally hardened in the form of soft and hard belt of 1 mm width alternatively along y direction. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48795. 相似文献
15.
16.
Sadao Hibi Takahiro Niwa Jun Mizukami Chi Wang Thein Kyu 《Polymer Engineering and Science》1995,35(11):911-920
The mechanisms of plastic deformation in cold-rolled ultrahigh molecular weight polypropylene (UHMWPP) have been explored by means of wide angle X-ray (WAXD) pole figures. The melt crystallized UHMWPP slabs were rolled unidirectionally in a two-roll mill at 408 K as well as in the cross (transverse) direction. In the unidirectional rolling, all reciprocal lattice vectors of (110), (040), and (130) were found to orient preferentially in the film normal (thickness) direction. The cross-rolling of UHMWPP shows the preferential orientation of the above plane normals in the film thickness direction, but the distribution of poles broadens toward the transverse direction. Such orientation behavior is very different from that of conventional cold-rolled polypropylene. Various orientation mechanisms involving the orientation of lamellae in the film plane, twinning of the (110) plane and slippage mechanisms have been taken into consideration to account for the observed pole figures. A theoretical simulation has been carried out based on an orientation distribution function approach by introducing a slippage angle along the maximum shear stress in conjunction with intralamellar slip around the transverse direction. This model simulation conforms closely with the experimental WAXD pole figures of the (110), (040), and (130) planes. 相似文献