Simulation-Based Investigation of Crack Formation in Forged MB15 Magnesium Alloy

In the process of riveting an MB15 forging die,cracks were discovered emerging along the longitudinal direction and near the riveting hole.Through fracture analysis,microscopic observation,energy spectrum analysis,metallographic examination,and hardness test,the properties and causes of the cracks are discussed.The results indicate that the cracking type is intergranular brittle cracking,occurring during the forging stage.Furthermore,the recrystallization at the crack site is found to be incomplete,which is attributed to the low deformation temperature.

老年公寓建筑数字孪生模型联合仿真疏散模拟方法

建筑数字孪生模型(BDT)是数字孪生(DT)应用到建筑业中与BIM结合的集成模型,能反映现实建筑运营情况.在数字孪生驱动下老年公寓消防安全和居住质量能得到进一步提升,因此提出一种老年公寓数字孪生模型联合仿真疏散模拟方法,用于老年公寓消防安全评估和设计优化.为验证方法可实施性,以大庆市某老年公寓为例,利用BDT模型和BIM分别进行仿真模拟,结果显示两者疏散时间相差较大,影响到其消防安全性判断,老年公寓BDT模型联合仿真模拟相比于其BIM模型单一空间仿真模拟,更能真实反映老年人群在火灾场景下疏散情况,根据方法框架得出算例老年公寓存在消防安全问题,提出消防改造和疏散优化策略并验证.

Effect of heat treatment on the microstructure and mechanical properties of a multidirectionally forged Mg-Gd-Y-Zn-Zr-Ag alloy

Multidirectional forging(MDF)was successfully applied to fabricate large-size Mg-Gd-Y-Zn-Zr-Ag alloy in this work and effects of T4,T5 and T6 treatments on the microstructure and mechanical properties of the as-forged alloy were analyzed.Results show that dynamic recrystallization(DRX)occurs and second phase particles precipitate along the grain boundary during the MDF process.After annealing treatment(T4),the volume fraction and size of dynamic precipitates slightly increase at a lower temperature(430℃)compared with those of MDFed sample,while they are dissolved into theα-Mg matrix at a higher temperature(450℃).At the meantime,short plate-shaped long-period stacking ordered(LPSO)phases are observed in the DRX grains of the MDFed sample and then dissolved into theα-Mg matrix during annealing at both temperatures.Typical basal texture is identified in the MDFed sample,but the basal pole tilts away from final forging direction and rare-earth texture component with<1121>orientation parallel to penultimate forging direction becomes visible after annealing.The T6 sample annealing at 430℃for 4 h and ageing at 200℃for 34 h exhibits the superior strength and ductility in this study.The ultimate tensile strength,tensile yield strength and elongation to failure,which is 455 MPa,308 MPa and 7.7%,respectively,are overall improved compared with the directly-aged(T5)sample.This paper provides a superior heat treatment schedule to manufacture high-performance large-scale Mg-Gd-Y-Zn-Zr-Ag components for industrial production.

Texture Engineering to Boost the Thermoelectric Properties

A round 60% of useful energy is wasted in industry, homes, or transportation. Therefore, there has been increasing attention on thermoelectric materials for their ability to harvest waste heat into useful energy. The efficiency of a thermoelectric material depends on its electrical conductivity, Seebeck coefficient, and thermal conductivity in a conflicting manner which results in efficiency optimization challenges. Single crystals and polycrystalline layered materials have comparatively better thermoelectric and mechanical properties in a certain direction. Texture engineering is a special strategy that allows the exploitation of superior material properties in a specific direction. Texturing could be achieved by various sintering and deformation methods, which yield defects improving thermoelectric and mechanical properties. The results show that for(Bi,Sb)_(2)Te_(3), Bi_(2)(Se,Te)_(3), C uSbSe_(2), and SnSe, significant enhancement in the thermoelectric figure of merit is achieved by enhancing the preferred orientation. Texture engineering provides a wide range of strategies to elevate the zT of anisotropic materials to values comparable to those of their single crystalline counterparts.

Effect of nitrogen content on the microstructure and mechanical properties of titanium-bearing nonquenched and tempered steel after hot forging

The microstructure and mechanical properties of titanium(Ti)-bearing medium-carbon nonquenched and tempered steel with different nitrogen content before and after hot forging were investigated through smelting,forging,and laboratory tests.The results show that the grain size of nonquenched and tempered steel was gradually refined,and the ferrite content gradually increased with an increase in nitrogen content.The grain size of the material with low nitrogen content increased abnormally,and its impact properties significantly decreased after hot forging.The grain size of nonquenched and tempered steel with higher nitrogen content was slightly larger than that before forging,and the tensile and yield strength increased,but the impact toughness was not significantly reduced.The Ti-bearing nonquenched and tempered steel showed better strength and toughness after hot forging with the addition of 0.010%0.015%nitrogen.

Blockchain-Based Certificate Authentication System with Enabling Correction

Blockchain has proven to be an emerging technology in the digital world, changing the way everyone thinks about data security and bringing efficiency to several industries. It has already been applied to a wide range of applications, from financial services and supply chain management to voting systems and identity verification. An organization must verify its candidates before selecting them. Choosing an unqualified candidate can ruin an organization’s reputation. In this paper, a blockchain-based academic certificate authentication system will be used to ensure authenticity and make the assertion of the decentralized system secure. However, the system will generate, authenticate and make corrections on academic certificates. Ultimately, some blockchain-based authentication systems already exist, they can’t correct any errors that occur during generation. A blockchain-based certificate authentication system was built using blockchain technology. Where admin could generate, authenticate and correct the certificate if necessary. The admin can also check how many times a certificate has been modified. Other users can only check the authenticity of the certificates. We’re using two blockchains to enable corrections. Blockchain technology can successfully implement a certificate authentication system. This system will eliminate doubts about the authenticity of certificates, provide fast responses, and ensure reliable and secure storage. The proposed system will help in many ways, such as providing a user-friendly university admission, and smooth job hiring process, etc. In conclusion, our proposed system can permanently eradicate certificate forgeries and create and promote trust in society.

桌面式五轴联动数控加工中心

当前数控加工向高精度、高速度、高柔性、体系开放化方向发展。五轴联动数控机床可以加工工艺复杂的零件,但因技术难度大、造价昂贵,致使大多数高等院校无法购买,这阻碍了五轴联动数控机床先进制造技术在国内的普及,也阻碍了中国制造业的快速发展。本产品作为新一代桌面式微小型数控机床,主要运用于高校教学和实验等场景。

Fostering Chinese National Unity:Advocating the National Common Language and Writing System for Heightened Community Awareness

The promotion of the national common language and writing system stands as a cornerstone in cultivating a sense of community among the Chinese nation.The national common language and writing system,serving as a potent vehicle for cultural dissemination and linguistic communication,acts as a crucial bridge fostering unity,mutual support,cultural exchange,and cohesion among diverse ethnic groups.Its widespread promotion not only reinforces the cohesion of the Chinese nation but also plays a pivotal role in fortifying national and cultural identity.The advocacy and dissemination of the national common language and writing system contribute significantly to enhancing the sense of community within the Chinese nation.This concerted effort serves as an internal driving force,creating a positive feedback loop that strengthens both national identity and the cultural bonds shared by the Chinese people.The reciprocal relationship between the promotion and popularization of the national common language and writing system reinforces a mutual sense of assistance and reciprocity.This bidirectional dynamic propels a synergistic interplay,fostering a beneficial cycle in the promotion and widespread adoption of the national common language and writing system.In essence,the promotion and popularization of the national common language and writing system not only contribute to its advancement but also serve to deepen the sense of community within the Chinese nation.This reciprocal interaction between the two elements establishes a robust foundation for nurturing a strong and cohesive Chinese community.

芯辊进给方式对辗环成形的影响

芯辊进给速度是径轴向环形辗扩成形的重要工艺参数。本文根据热辗扩的成形特点,用锻造软件Forge对芯辊三种不同进给方式(恒定进给速度、恒定每转进给量、恒定外半径增长速度)时径轴向辗环过程进行了数值模拟,分析了三种不同的芯辊进给方式对辗环成形的影响。结果表明,芯辊以恒定外半径增长速度进给时,轧件温差为88.738℃,是三种进给方式中温差最大的。这不利于控制轧制过程中温度的稳定性。

矿用液压软管接头芯子径向锻造工艺的研究

目的随着我国煤炭、钢铁业的新发展,矿用液压软管接头因更换快、使用量大,迫切需要新的成形工艺。方法针对KJ-25型液压软管接头芯子,提出了一种采用径向锻造近净成形制造毛坯的工艺。通过三维有限元软件FORGE建立了工艺的三维有限元模型,并对成形力、工件温度及应力状态进行了分析。结果有限元模拟结果表明:径向锻造生产的坯料较切削加工可节材37%,温锻时单个锤头锻造力仅为37.3 t。结论径向锻造工艺适用于同类型软管接头芯子的毛坯制造。

深型腔模具精密加工技术的研究与实现

针对淬硬工具钢切削性能差、深型腔模具加工廓形精度不易保证等问题,提出了一种深型腔模具精密高速加工工艺优化技术。该技术根据构建的加工刀轨长度以及刀具悬伸长度与型腔加工廓形误差之间的数学模型,计算随加工刀轨长度变化的廓形误差值,设计瞬时的螺旋线加工刀轨,运用曲线过渡法,生成了适合深型腔模具精密高速加工的优化刀轨。基于米克朗Duro800高速加工机床,对内星轮模具型腔进行精密加工,结果表明,加工精度可提高IT1～2级,表面粗糙度Ra≤0.8。

基于Forge的皮带轮旋压成形仿真分析

分析了某型皮带轮的旋压成形原理,运用有限元软件Forge建立了皮带轮旋压成形仿真分析模型,对其在不同旋压时间下的成形形状、等效应力、等效塑性应变及材料分布特性进行了仿真。结果表明:随着旋压不断进行,高速旋轮不断对皮带轮毛坯进行挤压,皮带轮槽逐渐成形;等效应力及等效塑性应变逐渐增加,最大值基本分布在轮槽上,工艺参数对皮带轮旋压成形材料分布均匀性影响较大。

基于Forge的带轮锻压成形有限元仿真

分析了某型带轮的锻压工艺,运用锻压有限元分析软件Forge建立了带轮镦粗、冲孔、环轧等仿真模型。对其在不同工序不同锻压时间下的成形形状、温度分布进行了有限元仿真,分析了带轮锻压成形形状及温度变化规律。

基于Simufact Forging高铁轮毂锻压成形工艺仿真

基于Simufact Forging有限元分析软件对高铁轮毂成形过程进行了仿真,着重研究了轮毂辗扩过程中的等效塑性应变、等效应力及材料流动。结果表明:高铁轮毂在辗扩过程中材料整体变形基本一致,可以获得较好的力学性能;随着锻压成形不断的进行,轮毂内圈塑性应变逐渐变大;成形过程中整个轮毂应力分布较为均匀。

基于Forge的铝合金轮毂温锻成形模拟

铝合金轮毂形状复杂、强度刚度要求高。本文分析了6061铝合金轮毂温锻成形工艺。运用模拟软件Forge建立了铝合金轮毂预锻、终锻成形有限元仿真模型,分析了预锻、终锻成形工艺过程中的温度、等效应力分布。结果表明:铝合金轮毂在预锻、终锻成形过程中,整体温度偏差较小;不同成形阶段和不同成形部位,轮毂等效应力值不同;轮毂结构及温锻成形工艺参数对铝合金轮毂温锻件影响较大。

基于Forge的止动片冷锻冲裁成形数值仿真

针对有孔较厚板材的成形问题,结合冷锻及冲裁工艺特点得到了某型止动片有孔板材冷锻冲裁成形工艺,分析了其冷锻冲裁成形原理。运用仿真软件Forge建立了止动片冷锻冲裁成形数值仿真模型,对其在不同冷锻冲裁时间下的等效应力、等效应变和应变能变化规律以及成形损伤特性进行了研究。结果表明:止动片在不同冷锻冲裁时间下,其等效应力、等效应变及应变能分布区域存在差异,但等效应力、等效应变及应变能变化趋势基本一致,最大值都出现在冲裁孔边缘。

Novell PlateSpin Forge系统在气象信息处理中的应用

近年来,随着贵州省气象局气象信息系统的飞速发展,大量的实时气象数据的采集、传输、存储快速成长为支撑当代气象业务的主要手段,计算机的广泛应用和进一步发展对核心业务系统的稳定性和安全性要求越来越高。本文通过Novell PlateSpin Forge系统在气象信息网络中的应用,分析了在气象业务备份容灾系统的实现方式。

借助Sound Forge软件实现3DS MAX中声音与动画的完美结合

3ds max是一款功能强大的三维动画制作软件,然而其本身并没有对声音文件的处理功能,利用Sound Forge这款功能强大的音频处理软件,实现对声音文件的处理,把处理后的声音插入到3ds max中,实现3ds max中声音与动画的完美结合.

培养孩子编织、烹饪、种植、拍摄等技能 海外兴起“终极创造家”产品

今年,培养儿童掌握烹饪、设计、种植,以及创作实体/虚拟艺术品等技能的产品和游戏在海外市场热卖。美国玩具协会将这股潮流命名为＂终极创造家＂。这一潮流的兴起源于这类产品可以让孩子积极地进行创造性思考,并获得不俗的动手能力。此类潮流产品涉及DIY、构建、娃娃等多个类别,甚至还囊括了那些融入3D打印理念的产品。