Implicit Analysis in LS-DYNA®
Instructor
- Dr. Nils Karajan
Implicit Analysis in LS-DYNA®
Prerequisites
- Basic knowledge of LS-DYNA
Syllabus
With this seminar we aim to give you an overview of the possibilities and limits of implicit simulations using LS-DYNA. In recent years, the simulation possibilities in LS-DYNA using implicit time integration have been enhanced extensively. Some areas of application for implicit analyses include linear and non-linear static and transient dynamic computations, natural frequency analyses, springback and initialization of systems with preload. Good scalability is observed on many CPU cores, which allows for the treatment of large scale problems with millions of unknown degrees of freedom. The course is recommended for you if you intend to use LS-DYNA to carry out implicit simulations. Examples will be given during the seminar to illustrate the functionality of the implicit options.
Content
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Introduction to the implicit solver
- Theory & comparison to explicit time integration
- Overview of implicit analysis types, applications, & involved implicit control keywords
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Linear static analysis
- Options, linear elements, boundary constraints, direct/iterative solver settings, memory, accuracy
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Dynamic implicit analysis
- Available time integration schemes (Newmark, Bathe, Hilber-Hughes-Taylor)
- Switching between dynamic and static analysis, input parameters, lumped/consistent mass matrix
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Nonlinear implicit static & dynamic analysis
- Origins of nonlinearity & comparison to linear analysis
- Nonlinear solution procedure: Newton based schemes, BFGS
- Convergence, tolerances, output, automatic, & manual time step control
- Eigenvalue analysis: options, modeling aspects, intermittent output
- Modal analysis, linear buckling
- Nonlinear buckling with arclength solvers
- Frequency response function
- Switching time integration scheme: implicit/explicit, explicit/implicit
- Element types for linear & nonlinear analysis
- Material models for implicit analyses
- Contact types for implicit: options, tied contacts, sliding contacts with Mortar option
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Troubleshooting convergence problems
- tips & tricks
- Miscellaneous: pre-stress, thermal load, performance, etc.
- Final guidelines with checklist of most important settings for implicit calculations