Skip to main content

NVH, Fatigue, and Frequency Domain Analysis


  • Yun Huang, Ph.D.

NVH, Fatigue, and Frequency Domain Analysis


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.


  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.)