共查询到17条相似文献,搜索用时 132 毫秒
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转向架构架焊接时形成熔合不良、气孔等缺陷是疲劳裂纹萌生和扩展的本质来源之一。以客车非动力转向架构架的铸造部件疲劳寿命为考察对象,对制动夹钳吊座用G20Mn5铸钢材料进行高周疲劳试验及断裂力学试验。依据构架焊接质量探伤结果进行缺陷的规则化处理,在制动夹钳吊座与横梁焊缝热影响区等应力热点区域置入不同深度的裂纹,考虑实测8级载荷谱作为制动工况输入,利用经典Paris疲劳裂纹扩展模型,在损伤容限框架内估算含焊接缺陷的制动夹钳吊座的剩余寿命。结果表明:当制动夹钳吊座与横梁焊缝处的原始铸造缺陷小于0.5 mm时,属于安全尺寸;而初始裂纹深度为1 mm的裂纹扩展到1 mm时的剩余寿命约为7098万km,超过现役焊接构架设计寿命。可见,疲劳寿命能满足设计寿命指标,并具有一定的安全裕度。 相似文献
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针对轨道交通车辆制动夹钳单元在随机振动工况下的疲劳分析提出频域方法。利用模态分析和随机响应分析,获得关键位置的应力响应功率谱密度曲线,通过Rayleigh模型、Dirlik模型和Steinberg的“三区间”模型,分别计算应力幅值概率密度以及疲劳累积损伤,并通过加速失效试验对3种模型的预测结果进行对比。结果表明:该频域分析方法能够对制动夹钳的结构疲劳失效过程提供合理预测,相比Rayleigh模型、Dirlik模型和“三区间”模型的分析准确性更高。 相似文献
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为了分析制动支管开裂是否由焊接工艺引起,采用常用的焊条电弧焊、MAG焊、TIG焊进行了几组试验.结果表明均能获得较好的焊接接头,焊接工艺不是引起制动管开裂的原因.通过对制动管开裂的试验分析,得出是由于缝隙腐蚀所引起的疲劳裂纹,并提出采用脉冲TIG焊专机、焊端倒角、TIG重熔或涂密封胶、减少接头应力集中、细化工艺文件、加... 相似文献
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对研制的时速250公里复兴号中国标准动车组用铸钢制动盘进行了显微组织及晶粒度检验、力学性能试验、热物理性能试验、内部缺陷检验及热疲劳性能试验。结果表明:所研制的铸钢制动盘组织为致密的回火索氏体,具有较高的强度、伸长率、冲击吸收能量、比热容和热扩散系数,内部缺陷符合行业标准的技术要求,与进口制动盘相比具有更好的热疲劳性能。制动盘1∶1制动动力试验及疲劳试验和60万公里运用考核结束后制动盘摩擦面没有出现热斑、划伤、热裂纹等不良现象,可以满足时速250公里动车组使用要求。 相似文献
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机械补偿机构是金属板材折弯机中普遍使用的挠度补偿机构,它可以减小折弯工件时滑块与工作台挠曲变形带来的不利影响,提高折弯机的制件精度.折弯过程中,折弯机机械补偿机构受到反复挤压与拉伸,容易产生强度和疲劳破坏,机械补偿机构的设计中对其进行疲劳寿命的估算与校核是必不可少的一个环节.本文采用三维弹性接触有限单元法对某型机械补偿机构的折弯过程进行模拟,得出折弯过程中机械补偿结构的最大接触应力,将得到的最大接触应力代入材料的S-N疲劳寿命公式,计算得出补偿机构的疲劳寿命.分析结果表明:该机械补偿机构的疲劳寿命满足设计要求,并与试验结果具有较好的吻合程度.该方法对折弯机机械补偿机构的疲劳寿命的估算与校核具有较大的指导意义. 相似文献
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In the case of employing brake discs as a key component of mechanical brake equipment, the initiation of thermal cracking
owing to repetitive thermal shock generated during braking may potentially lead to higher maintenance costs, worsened braking
performance, and greater risk of railway accidents. The purpose of this study is to gain basic data to facilitate application
of compacted vermicular (C. V.) graphite cast iron to brake discs in order to obtain high thermal crack resistance and improved
lifetime. To this end, this study developed three types of C. V. graphite cast iron with differing content of key elements,
including Ni, Cr, and Mo. Each test specimen underwent numerous tests for evaluation of materials characteristics, and the
results were compared with those obtained for existing materials. The test results show that the thermal fatigue lifetime
of material C is nearly double that of the conventional material. This demonstrates the suitability of material C as a material
for brake discs in mid- to high-speed railway vehicles. 相似文献
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LIUJian-xiu GAOHong-xia WEIXiu-lan 《材料热处理学报》2004,25(5):126-129
The experiment is conducted on MM-1000 friction test machine, which tests friction wear property of copper-based brake materials by powder metallurgy at different brake speeds. It shows that the coefficient of friction and wear volume are greatly influenced by brake speed. When the brake speed is 4000 r/min, which is a bit higher, the material still has a higher coefficient of friction with 0.47. When the brake speed is over 4000r/min. the coefftcient of friction decreased rapidly. When the brake speed is 300Of/rain, the material‘s wear is in its minimum. That is to say no matter how higher or lower the brake speed is the wear volume is bigger relatively. With the brake speed of the lower one it mainly refers to fatigue wear; while of higher one it mainly refers to ahradant and oxidation wear. 相似文献
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驱动桥综合性能试验台计算机控制系统的研制 总被引:1,自引:0,他引:1
针对驱动桥的总成性能,采用计算机测控系统实现了对驱动桥制动性能和疲劳性能的检测。介绍了性能试验台的总体结构及相应的软硬件设计方案。 相似文献