机械5

目录 摘要III Abstract IV 1绪论1 1.1研究背景1 1.2国内外MSD剩余强度研究现状2 1.3本文研究内容3 2广布疲劳损伤的敏感结构4 2.1引言4 2.2敏感结构的三维模型4 2.3计算模型7 2.4本章小结8 3 MSD剩余强度分析理论9 3.1引言9 3.2应力强度因子9 3.3相互影响因子13 3.4剩余强度理论14 3.5本章小结20 4有限元建模21 4.1引言21 4.2 ABAQUS验证21 4.3建模过程23 4.4本章小结29 5 MSD剩余强度分析30 5.1引言30 5.2建模数据30 5.3应力强度因子分析32 5.4剩余强度签到股分析37 5.5本章小结46 6结束语47 6.1本文的主要贡献47 6.2需要进一步研究的问题47 参考文献48 致谢50 MSD剩余强度分析 摘要 随着老龄飞机机队老化的发展，其可持续适航问题已成为民用航空业和公众关注的焦点。对于老龄飞机来说，广布疲劳损伤是一种普遍而又复杂的问题。它是许多老龄飞机中存在的一种非常典型的损伤形式。广布疲劳损伤会导致飞机结构的破损。因此，研究广布疲劳损伤结构的剩余强度问题拥有较大的前景和实用意义。本文在前人的研究发现的基础上，对本课题进行试验，各个环节都有所依靠或予以验证，从而表明本文数据的正确性，可靠性。主要针对多裂纹造成的多部位损伤（MSD）剩余强度的问题，进行了基于三维软件和ABAQUS有限元分析软件，origi
n数据处理软件，对老龄化飞机结构建立有限元模型；在了解材料参数，断裂参数以及边界条件的基础上，讨论孔边裂纹的相对位置和长度对应力强度因子的影响规律，并进行净截面应力强度和剩余强度分析得出一系列对工程应用具有实用价值的结论。 关键词：广布疲劳损伤，多部位损伤，应力强度因子，净截面，剩余强度，有限元分析 MSD residual stre
ngth a
nalysis ABSTRACT With the passage of time, the expa
nsio
n of fleets of older aircraft a
nd their co
nti
nued airworthi
ness have become the focus of atte
ntio
n of the civil aviatio
n commu
nity a
nd the ge
neral public. For agi
ng aircraft, widespread fatigue damage is a commo
n a
nd complex problem. It is a very typical form of damage that exists i
n ma
ny older aircraft. Widespread fatigue damage ca
n compromise the i
ntegrity of the aircraft structure. Therefore, it is of great e
ngi
neeri
ng sig
nifica
nce a
nd practical value to study the residual stre
ngth of fatigue damage structures. This article starts from the research basis of the predecessors a
nd tests this topic. Every li
nk has bee
n relied o
n or verified to show the correct
ness a
nd reliability of the data. Mai
nly for the problem of multi-slice damage (MSD) residual stre
ngth caused by multiple cracks, based o
n three-dime
nsio
nal software a
nd ABAQUS fi
nite eleme
nt a
nalysis software, origi
n data processi
ng software, established a fi
nite eleme
nt model for the agi
ng of the aircraft structure; i
n u
ndersta
ndi
ng the material parameters, fracture Based o
n the parameters a
nd bou
ndary co
nditio
ns, the i
nflue
nce of the relative positio
n a
nd le
ngth of the hole cracks o
n the stress i
nte
nsity factor is discussed, a
nd the a
nalysis of the
net sectio
n stress i
nte
nsity a
nd residual stre
ngth yields a series of practically useful co
nclusio
ns for e
ngi
neeri
ng applicatio
ns. Key words: exte
nsive fatigue damage， multi-site damage ，stress i
nte
nsity factor，
net cross sectio
n， residual stre
ngth， fi
nite eleme
nt a
nalysis