NVH, Fatigue, and Frequency Domain Analysis

NVH, Fatigue, and Frequency Domain Analysis

Syllabus

This course is rec­om­mend­ed for at­ten­dees who want to run NVH or oth­er fre­quen­cy do­main vi­bra­tion, fa­tigue and acoustic sim­u­la­tion prob­lems with LS-DY­NA. This course is use­ful for ap­pli­ca­tions in­clud­ing ve­hi­cle NVH, air­craft /­ space­craft vi­bro-acoustics, en­gine noise sim­u­la­tion, and ma­chine vi­bra­tion test­ing and sim­u­la­tion. This course in­tro­duces you to the fre­quen­cy do­main vi­bra­tion, fa­tigue and acoustic fea­tures of LS-DY­NA and gives a de­tailed look at the ap­pli­ca­tion of these fea­tures to ve­hi­cle NVH sim­u­la­tion and dura­bil­i­ty analy­sis.

Content

1. In­tro­duc­tion
   1. NVH the­o­ry and lab test­ing tech­nol­o­gy
   2. Overview of LS-DY­NA fre­quen­cy do­main fea­tures and ap­pli­ca­tions
   3. Fre­quen­cy do­main analy­sis vs. time do­main analy­sis
   4. Fouri­er trans­form
2. FRF
   1. Modal su­per­po­si­tion method
   2. Damp­ing (vis­cous damp­ing, struc­tur­al damp­ing)
   3. Nodal force /­ re­sul­tant force FRF
3. SSD
   1. Large mass method
   2. Equiv­a­lent Ra­di­at­ed Pow­er (ERP)
   3. Mode ex­pan­sion with LS-Pre­Post
   4. Mode con­tri­bu­tion ex­pan­sion plot
   5. Di­rect SSD
4. Ran­dom vi­bra­tion with PSD load­ing
   1. Cor­re­lat­ed and un­cor­re­lat­ed mul­ti­ple ex­ci­ta­tion
   2. Acoustic waves
   3. Pre-stress con­di­tion
5. Acoustics
   1. BEM, FEM
   2. Vi­bro-acoustics
   3. In­ci­dent waves
   4. Acoustic pan­el /­ el­e­ment con­tri­bu­tion analy­sis
   5. ATV and MATV
   6. Fre­quen­cy weight­ed SPL (dB)
   7. Ra­di­at­ed sound pow­er, ra­di­a­tion ef­fi­cien­cy
   8. Acoustic eigen­val­ue analy­sis
6. Re­sponse spec­trum analy­sis
   1. In­put earth­quake spec­trum
   2. Modal com­bi­na­tion meth­ods (SRSS, CQC, etc.)
   3. Mul­ti-in­put spec­tra
   4. DDAM
7. Fa­tigue
   1. Fa­tigue the­o­ries
   2. Fa­tigue analy­sis in har­mon­ic /­ ran­dom vi­bra­tion en­vi­ron­ment
   3. Min­er's rule
   4. Dir­lik Method
   5. Time do­main fa­tigue (based on stress /­ strain)
   6. Mul­ti­ax­i­al fa­tigue
   7. Mean stress cor­rec­tion
8. Ad­vanced top­ics
   1. Sta­tis­ti­cal En­er­gy Analy­sis (SEA)
   2. Brake squeal analy­sis
   3. NVH analy­sis based on IGA
9. Au­to NVH ex­am­ples
   1. FRF on BIW
   2. Noise Trans­fer Func­tions (NTF)
   3. Ve­hi­cle in­te­ri­or noise
   4. Muf­fler Trans­mis­sion Loss Analy­sis
10. Work­shop
    1. Hands-on ex­er­cise
    2. Post-pro­cess­ing of bi­na­ry and ASCII data­bas­es (d3ssd, d3acs, d3ftg, nod­out_­ssd, elout_­ssd, etc.)