ls-dyna預(yù)應(yīng)力加載介紹相當(dāng)詳細(xì)ppt課件

1、nStress in Solid Cross-sectionnForce in BeamsDR convergesSIDR = 1 (DR phase)SIDR = 0 (transient phase)Dynamic Relaxation information is writtento the screen. The transient phase starts when the convergence tolerance or a Specified termination time is reached. Convergence plot from relax fileKinetic

2、Energy plot from relax filengContactGround is constrained One of the tires from NCACs Ford 250 was used inthis example but without the control volume. A gravity load is applied in the transient phase as a constant curve, which makes the tire bounce during the simulation (time =1) as seen when plotti

3、ng the Z-displacement for a node on the tirerim. This model is used to investigate the behavior of Dynamic Relaxation.Node ConsideredA No DRB With DRnThe value of DRTOL offers a tradeoff between run time and amplitude of residual dynamic oscillation.Load TimePreload Transient Load Mass Damping Coef

4、TimeLoad Timet1t1t2t2nnStep size has units of time if dynamics is invoked.nUsing only data from the d3plot database, LS-PrePost can output a dynain file via Output Format: Dynain Ascii Write.TimeTimeDynamic relaxation (LCID1) + Transient Phase (LCID2)Transient Phase Only (LCID2) if LCID1=0TimeContac

5、t Stiffness Scale FactorContact Stiffness Scale FactorContact Stiffness Scale Factor1.01.01.0Example:ftp.lstc/anonymous/outgoing/jday/erf.k.gznContact damping (VDC) and/or *DAMPING_PART_STIFFNESS may be required to attain convergence during the dynamic relaxation analysisExample: ftp.lstc/an

6、onymous/outgoing/jday/bolt.initial_stress_section.4not1.k.gzExample of preloaded boltsTarget bolt stress is achieved without multiple trial simulations.nFor models with contact, damping in the contact (VDC=20) is recommended. n*DAMPING_PART_STIFFNESS may promote convergence during DR phase.Example: ftp.lstc/anonymous/outgoing/jday/ini