共查询到20条相似文献,搜索用时 78 毫秒
1.
2.
3.
4.
摘自《塑性工程学报》 《钛工业进展》2013,(5):43-43
成形极限是板材成形中十分重要的性能指标和工艺参数,反映了变形过程中板材在塑性失稳状态前的最大变形程度,是进行模具设计和工艺设计的主要依据。目前,国内外学者对室温条件下的板材成形极限做了诸多研究,而热态成形极限由于受温度、润滑、氧化以及应变量测量方法等诸多影响,相关研究相对较少。 相似文献
5.
6.
本文基于一种集中失效模型,结合CMPT和Hosford非二次各向异性屈服函数,假定材料服从各方向同性加工硬化,提出了一种形式上相对简单,便于工程应用的成形极限图的方法。对比该方法的理论预测和实验实测结果,表明本文采用的方法是有效的。 相似文献
7.
8.
9.
10.
11.
Hydroforming process is most widely used in automotive industries. The current work involves the formability evaluation of DQ Steel and Al 5182 tubular blanks using the bulge test simulation done on PAM-STAMP 2G solver. The dependence of stress based forming limit diagrams are also evaluated in complex loading paths in case of hydro-forming as they are independent of strain paths. 相似文献
12.
13.
Yoshitaka Suetake 《Canadian Metallurgical Quarterly》2002,128(2):231-239
In this paper, a simple element-free method using the Lagrange polynomial is proposed, in which finite-element subdivisions are not required. Most ordinary element-free approaches are based on the moving least squares (MLS). The present procedure, however, does not employ MLS interpolants. Instead of MLS, the Lagrange polynomial is employed here for the discretization. The Lagrange polynomial makes it possible to connect an approximate solution and its derivatives at any point directly with nodal values. Therefore, the essential boundary conditions can be easily satisfied, while it is quite difficult to do so in the ordinary element-free method. In addition, it is proved that the Lagrange basis is consistent. Consequently, the reproducing condition is satisfied by the Lagrange interpolation. Several numerical examples are presented in order to demonstrate the efficiency of the present procedure. It follows from numerical evaluations that relatively good approximation can be achieved in the nonlinear analyses of beams and plates. 相似文献
14.
在地质勘探过程中,由于技术、设备的客观条件限制,造成了部分基础地质数据的缺失,这使得矿床建模时地质数据不够完整准确,直接影响了矿体形态及储量估值的精度。为了向矿床模型的构建环节提供完整且可信的基础地质数据,首先研究了地质缺失数据的产生机制,并通过对比分析期望-极大化算法(EM算法)、马尔可夫-蒙特卡洛方法(MCMC方法)以及BP神经网络等数据插补方法的特点及适用条件,提出了基于BP神经网络的地质缺失数据处理方法,构建了地质缺失数据处理的BP神经网络模型,并在山东某金矿进行了实际应用与模型验证。结果表明,模型可以实现地质缺失数据的部分插补,插补结果可信,可以有效解决因基础资料缺失所带来的地质数据不完整问题。 相似文献
15.
Jingee Park Jeounghan Kim Nhokwang Park Youngsuk Kim 《Metallurgical and Materials Transactions A》2010,41(1):97-105
As a lightweight material, magnesium is being increasingly used for automotive parts. However, due to a hexagonal-closed-packed
(hcp) crystal structure, in which only the basal plane can move, magnesium alloy sheets exhibit a low ductility and formability
at room temperature. Press forming of magnesium alloy sheets is conventionally performed at elevated temperatures of 200 °C
to 250 °C and thus is known as energy consumed forming. Therefore, in view of an energy saving forming technology, we study
magnesium alloy sheet forming by a rotational incremental sheet forming (RISF) at room temperature, where the rotational tool
generates local heat of specimen enough to accelerate plastic deformation. The flow curves of the magnesium alloy sheet are
obtained and calculated at elevated temperatures, while the yield loci of the magnesium alloy sheet are measured at room temperature.
Using RISF, a square cup of 80-mm width, 80-mm length, and 25-mm height is then formed from a magnesium alloy sheet at room
temperature. In addition, the strain distribution is obtained and compared with the forming limit curve (FLC) by considering
the effect of the tool radius and is found to effectively predict the forming limit of a magnesium alloy sheet in RISF. 相似文献
16.
17.
18.
19.
考虑传统的极限平衡法和FLAC二维非线性数值分析方法的优缺点,将边坡稳定性分析的Slide极限平衡法和FLAC2D强度折减法相结合,以某排土场为工程实际,进行了边坡在天然、天然地震、降雨和降雨地震四种不同工况下的稳定性验算比较;鉴于影响边坡稳定因素的不确定性,采用基于Spencer法的Mont-Carlo法进行了边坡可靠度指标的计算,并对强度参数C、(φ)和容重γ对边坡稳定的影响进行了分析,得出边坡稳定对内摩擦角(φ)的敏感性高于内聚力C的敏感性,而容重γ的影响较C、(φ)可忽略不计.该方法通过两者的相互校核,不仅给出边坡非线性应力-应变关系和安全系数来共同评价边坡的稳定性,而且结合排土场边坡安全系数的概率分析提供边坡潜在的失效概率使边坡稳定性评价更加科学、精确. 相似文献