STATSUB

Format

STATSUB(type) = option

Definitions

Comments

1. A METHOD entry to define the eigenvalue extraction method is required in addition to a STATSUB entry for a linear buckling solution subcase.
2. The following applies to STATSUB(BUCKLING):
   • STATSUB(BUCKLING) can only be used to reference buckling to linear static or nonlinear static (small displacement + N2S/S2S contact only) subcases.
   • A linear buckling solution cannot be performed on a linear static subcase that uses inertia relief.
3. The following applies to STATSUB(PRELOAD):
   • STATSUB(PRELOAD) can only be used to reference linear static or nonlinear static (small and large displacement + N2S/S2S contact only) subcases.
   • STATSUB(PRELOAD) can be used to apply preloading for linear static, normal modes, complex eigenvalue, direct frequency response, modal frequency response, direct transient response, modal transient response, linear buckling, and Component Mode Synthesis (CMS) solution sequences.
   • STATSUB(PRELOAD) can be used with the AMSES eigensolver.
   • Preloading applied to a normal modes subcase is not transferred to subsequent modal solution subcases (with the same modal space and boundary conditions) in the same input deck.
   • When STATSUB(PRELOAD) points to a nonlinear subcase with contact, the contact status is carried over to the current subcase in which this STATSUB(PRELOAD) is defined.
   When STATSUB(PRELOAD) is defined in a linear buckling subcase:

   • If the subcase referenced by STATSUB(BUCKLING), is a regular linear static subcase, initial stress stiffness produced with the subcase referenced by STATSUB(PRELOAD) is added to the subcase referenced by STATSUB(BUCKLING).
   • If the subcase referenced by STATSUB(BUCKLING) in the linear buckling subcase is a linear-static-preloaded linear static subcase, OptiStruct issues an error.
   • If subcase referenced by STATSUB(BUCKLING) in the linear buckling subcase is an NLSTAT subcase, OptiStruct issues an error.
   • If the subcase referenced by STATSUB(BUCKLING) in the linear buckling subcase is an NLSTAT-preloaded linear static subcase, the subcase referenced by STATSUB(BUCKLING) takes initial stress stiffness produced with the NLSTAT preloading, and STATSUB(PRELOAD) is ignored.
   • If STATSUB(PRELOAD) points to an NLSTAT subcase, OptiStruct issues an error.

   For more information on using a preloaded linear static analysis (with STATSUB(PRELOAD) pointing to large displacement nonlinear analysis) in buckling analysis, see the Linear Buckling Analysis User Guide.
4. The following applies to STATSUB(PRETENS)
   • STATSUB(PRETENS is supported for linear and nonlinear static subcases. Other subcase types can use STATSUB(PRELOAD), which refers to a pretension subcase, in order to incorporate the effect of pretensioning on natural frequencies, dynamic solutions, and so on.
   • STATSUB(PRETENS) can only reference a subcase that precedes the current subcase in the input deck.
   • STATSUB(PRETENS) along with PRETENSION and CNTNLSUB can be used to define complex pretensioning sequences, such as tightening and adjustment of bolts in sequence or in groups. STATSUB(PRETENS) controls the sequencing of pretensioning steps and CNTNLSUB controls the sequencing of nonlinear aspects (plasticity, contact with friction, and so on) for quite arbitrary loading scenarios.
5. STATSUB(STRUCTURE) is supported for Linear and Nonlinear Heat Transfer (steady-state and transient) Analysis.
6. STATSUB(BRAKE) can only be specified within a Modal Complex Eigenvalue Analysis subcase and can only reference a small displacement nonlinear static analysis subcase. For more information, refer to Brake Squeal Analysis and Complex Eigenvalue Analysis in the User Guide.
7. In subcases preloaded by Nonlinear analysis subcases with MODCHG, the preloaded subcases will have the corresponding removed elements greyed out in the H3D file. So any elements removed via MODCHG in nonlinear subcases referenced by STATSUB(PRELOAD), STATSUB(BRAKE), or STATSUB(BUCKLING) will be greyed out in the H3D file of the corresponding preloaded subcase.
8. The elements CELAS1, CELAS2, CMASS1, CMASS2, CONM1, CONM2, CBUSH, CVISC, CDAMP1, CDAMP2, CGAP, CGAPG, PLOTEL, CWELD, CSEAM, CFAST, and JOINTG do not contribute to the geometric stiffness matrix $K_{\sigma }$ . For more information, refer to Prestressed Linear Analysis and Linear Buckling Analysis in the User Guide.