木材紧固系统应力松弛的量化:铁路重点研究

IF 2.4 3区 农林科学 Q1 FORESTRY European Journal of Wood and Wood Products Pub Date : 2024-04-22 DOI:10.1007/s00107-024-02071-5
Rahat Mahmud Khan, Marcus S. Dersch, Alison C. Dunn
{"title":"木材紧固系统应力松弛的量化:铁路重点研究","authors":"Rahat Mahmud Khan,&nbsp;Marcus S. Dersch,&nbsp;Alison C. Dunn","doi":"10.1007/s00107-024-02071-5","DOIUrl":null,"url":null,"abstract":"<div><p>Elastic fasteners have been widely adopted in timber sleeper tracks in certain high-demand areas across North American freight network due to their excellent potential to mitigate rail-rollover derailments by resisting steering moment and rotation of rail from the vertical axis through intense elastic force to securely hold-down the rail to the sleeper baseplate. However, these systems have led to at least 13 derailments reported since 2000 because of sleeper baseplate spike fatigue failures. Previous spike-failure investigations established that the loss of friction at the baseplate-sleeper interface caused by the wave-action of rail was the major mechanism that transfers additional loads to the spikes, and results in spike stresses exceeding the endurance limits. Previous studies also demonstrated the positives of plate hold-down load on controlling spike stress levels; with this load being historically applied via spring washers. Although the static performance of such hold-down systems has been evaluated in the literature, the long-term, time dependent behavior has not been quantified previously. This paper quantifies the effects of timber sleeper species, spring washer resiliency, and installation load on stress relaxation of these systems over 1,000 h in the laboratory under constant climate conditions. Experimental data demonstrate the significant impact of installation load magnitude on relaxation performance – load retention of 96% and 67% observed under 11.1 kN (2,500 lbs.) and 66.7 kN (15,000 lbs.) installation load, respectively. However, the insignificant effect of spring resiliency on the relaxation behavior was reflected through a 2% only change in load retention over a four-fold change in resiliency. A 15% increase in load retention was achieved by using Red Oak in place of Mixed Hardwood which established sleeper species as a critical parameter in such applications. An assessment of an extended experimentation period (i.e., 2,450 h) was carried out to better estimate the end point of relaxation. The experiments were conducted in an environmental chamber that does not represent the harsh conditions (i.e., loads, vibrations, temperature, humidity, or moisture) of the revenue-service tracks. However, results from this work can reasonably be useful to guide the selection of appropriate components along with recommended installation loads for hold-down applications to improve the overall safety of timber sleeper tracks that leverage elastic fasteners.</p></div>","PeriodicalId":550,"journal":{"name":"European Journal of Wood and Wood Products","volume":"82 4","pages":"1213 - 1225"},"PeriodicalIF":2.4000,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Quantification of stress relaxation in a timber fastening system: a railway focused study\",\"authors\":\"Rahat Mahmud Khan,&nbsp;Marcus S. Dersch,&nbsp;Alison C. Dunn\",\"doi\":\"10.1007/s00107-024-02071-5\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Elastic fasteners have been widely adopted in timber sleeper tracks in certain high-demand areas across North American freight network due to their excellent potential to mitigate rail-rollover derailments by resisting steering moment and rotation of rail from the vertical axis through intense elastic force to securely hold-down the rail to the sleeper baseplate. However, these systems have led to at least 13 derailments reported since 2000 because of sleeper baseplate spike fatigue failures. Previous spike-failure investigations established that the loss of friction at the baseplate-sleeper interface caused by the wave-action of rail was the major mechanism that transfers additional loads to the spikes, and results in spike stresses exceeding the endurance limits. Previous studies also demonstrated the positives of plate hold-down load on controlling spike stress levels; with this load being historically applied via spring washers. Although the static performance of such hold-down systems has been evaluated in the literature, the long-term, time dependent behavior has not been quantified previously. This paper quantifies the effects of timber sleeper species, spring washer resiliency, and installation load on stress relaxation of these systems over 1,000 h in the laboratory under constant climate conditions. Experimental data demonstrate the significant impact of installation load magnitude on relaxation performance – load retention of 96% and 67% observed under 11.1 kN (2,500 lbs.) and 66.7 kN (15,000 lbs.) installation load, respectively. However, the insignificant effect of spring resiliency on the relaxation behavior was reflected through a 2% only change in load retention over a four-fold change in resiliency. A 15% increase in load retention was achieved by using Red Oak in place of Mixed Hardwood which established sleeper species as a critical parameter in such applications. An assessment of an extended experimentation period (i.e., 2,450 h) was carried out to better estimate the end point of relaxation. The experiments were conducted in an environmental chamber that does not represent the harsh conditions (i.e., loads, vibrations, temperature, humidity, or moisture) of the revenue-service tracks. However, results from this work can reasonably be useful to guide the selection of appropriate components along with recommended installation loads for hold-down applications to improve the overall safety of timber sleeper tracks that leverage elastic fasteners.</p></div>\",\"PeriodicalId\":550,\"journal\":{\"name\":\"European Journal of Wood and Wood Products\",\"volume\":\"82 4\",\"pages\":\"1213 - 1225\"},\"PeriodicalIF\":2.4000,\"publicationDate\":\"2024-04-22\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"European Journal of Wood and Wood Products\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s00107-024-02071-5\",\"RegionNum\":3,\"RegionCategory\":\"农林科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"FORESTRY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"European Journal of Wood and Wood Products","FirstCategoryId":"88","ListUrlMain":"https://link.springer.com/article/10.1007/s00107-024-02071-5","RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"FORESTRY","Score":null,"Total":0}
引用次数: 0

摘要

在北美货运网络的某些高需求地区,木质枕木轨道已广泛采用弹性紧固件,这是因为弹性紧固件通过强大的弹性力将钢轨牢固地固定在枕木底板上,从而抵御钢轨的转向力矩和从垂直轴上的旋转,具有减轻翻轨脱轨事故的巨大潜力。然而,自 2000 年以来,由于轨枕底板道钉疲劳失效,这些系统已导致至少 13 起脱轨事故。先前的道钉失效调查表明,钢轨的波浪作用导致底板与枕木接口处摩擦力减小,是向道钉传递额外载荷的主要机制,并导致道钉应力超过耐久极限。以前的研究也证明了钢板固定载荷对控制道钉应力水平的积极作用;历史上这种载荷是通过弹簧垫圈施加的。虽然文献中已经对这种压紧系统的静态性能进行了评估,但长期的、随时间变化的行为尚未量化。本文量化了木材枕木种类、弹簧垫圈弹性和安装荷载对这些系统在实验室恒定气候条件下 1000 小时应力松弛的影响。实验数据证明了安装荷载大小对松弛性能的显著影响--在 11.1 千牛(2,500 磅)和 66.7 千牛(15,000 磅)的安装荷载下分别观察到 96% 和 67% 的荷载保持率。然而,弹簧弹性对松弛行为的影响并不显著,这体现在弹性变化四倍时,负载保持率仅变化 2%。用红橡木代替混合硬木后,荷载保持率提高了 15%,这表明枕木种类在此类应用中是一个关键参数。为了更好地估计松弛的终点,对延长的实验时间(即 2450 小时)进行了评估。实验是在一个环境试验室中进行的,该环境试验室并不代表收入服务轨道的恶劣条件(即负荷、振动、温度、湿度或水分)。但是,这项工作的结果可以合理地用于指导选择适当的部件,以及为固定应用推荐安装载荷,以提高利用弹性紧固件的木枕轨道的整体安全性。
本文章由计算机程序翻译,如有差异,请以英文原文为准。

摘要图片

查看原文
分享 分享
微信好友 朋友圈 QQ好友 复制链接
本刊更多论文
Quantification of stress relaxation in a timber fastening system: a railway focused study

Elastic fasteners have been widely adopted in timber sleeper tracks in certain high-demand areas across North American freight network due to their excellent potential to mitigate rail-rollover derailments by resisting steering moment and rotation of rail from the vertical axis through intense elastic force to securely hold-down the rail to the sleeper baseplate. However, these systems have led to at least 13 derailments reported since 2000 because of sleeper baseplate spike fatigue failures. Previous spike-failure investigations established that the loss of friction at the baseplate-sleeper interface caused by the wave-action of rail was the major mechanism that transfers additional loads to the spikes, and results in spike stresses exceeding the endurance limits. Previous studies also demonstrated the positives of plate hold-down load on controlling spike stress levels; with this load being historically applied via spring washers. Although the static performance of such hold-down systems has been evaluated in the literature, the long-term, time dependent behavior has not been quantified previously. This paper quantifies the effects of timber sleeper species, spring washer resiliency, and installation load on stress relaxation of these systems over 1,000 h in the laboratory under constant climate conditions. Experimental data demonstrate the significant impact of installation load magnitude on relaxation performance – load retention of 96% and 67% observed under 11.1 kN (2,500 lbs.) and 66.7 kN (15,000 lbs.) installation load, respectively. However, the insignificant effect of spring resiliency on the relaxation behavior was reflected through a 2% only change in load retention over a four-fold change in resiliency. A 15% increase in load retention was achieved by using Red Oak in place of Mixed Hardwood which established sleeper species as a critical parameter in such applications. An assessment of an extended experimentation period (i.e., 2,450 h) was carried out to better estimate the end point of relaxation. The experiments were conducted in an environmental chamber that does not represent the harsh conditions (i.e., loads, vibrations, temperature, humidity, or moisture) of the revenue-service tracks. However, results from this work can reasonably be useful to guide the selection of appropriate components along with recommended installation loads for hold-down applications to improve the overall safety of timber sleeper tracks that leverage elastic fasteners.

求助全文
通过发布文献求助,成功后即可免费获取论文全文。 去求助
来源期刊
European Journal of Wood and Wood Products
European Journal of Wood and Wood Products 工程技术-材料科学:纸与木材
CiteScore
5.40
自引率
3.80%
发文量
124
审稿时长
6.0 months
期刊介绍: European Journal of Wood and Wood Products reports on original research and new developments in the field of wood and wood products and their biological, chemical, physical as well as mechanical and technological properties, processes and uses. Subjects range from roundwood to wood based products, composite materials and structural applications, with related jointing techniques. Moreover, it deals with wood as a chemical raw material, source of energy as well as with inter-disciplinary aspects of environmental assessment and international markets. European Journal of Wood and Wood Products aims at promoting international scientific communication and transfer of new technologies from research into practice.
期刊最新文献
Study on the rotational performance of steel hub joints of wood reticulated domes subjected to monotonic bending moment Understanding the adhesion performance of glued laminated timber manufactured with Australian softwood and high-density hardwood species Selected physical and mechanical properties of particleboards manufactured with addition of Betula bark post-extraction residues Image-based mesh generation for constructing a virtual representation of engineered wood product samples Effect of microwave-assisted softening on the physicochemical properties of Moso bamboo
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
已复制链接
已复制链接
快去分享给好友吧!
我知道了
×
扫码分享
扫码分享
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1