Oasys LS-DYNA Environment 8.1 VOLUME 3 ... - Oasys Software

More documents

Recommendations

Info

Oasys LS-DYNA Environment: User Guide (Version 8.1) *BOUNDARY This section applies to various methods of specifying either fixed or prescribed motion boundary conditions. Restraints can be set up as a *BOUNDARY_SPC_NODE section, however, a *DEFINE_COORDINATE_SYSTEM is required to define the global coordinate system. For compatibility with older versions of LS-DYNA, it is still possible to specify some nodal boundary conditions in the *NODE card section. *CONSTRAINED This applies constraints within the structure between structural parts. For example, nodal rigid bodies (*CONSTRAINED_NODAL_RIGID_BODY_OPTION), rivets (*CONSTRAINED_RIVET), spotwelds (*CONSTRAINED_SPOTWELD), linear constraints (*CONSTRAINED_RIGID_BODIES), adding extra nodes to rigid bodies (*CONSTRAINED_EXTRA_NODES_OPTION) and defining rigid body joints (*CONSTRAINED_JOINT_OPTION) are all options in this section. This section applies constraints within the structure between structural parts. For example, nodal rigid bodies, rivets, spotwelds, linear constraints, tying a shell edge to a shell edge with failure, merging rigid bodies, adding extra nodes to rigid bodies and defining rigid body joints are all options in this section. *CONTACT This section is divided into three main sections. The *CONTACT section allows the users to define a total of 24 different contact types. These contact options are primarily for treating contact of deformable to deformable bodies, single surface contact in deformable bodies, deformable body to rigid body contact, and tying deformable structures with an option to release the tie based on plastic strain. The surface definition for contact is made up of segments on the shell or solid element surfaces. The *CONTACT_ENTITY section treats contact between a rigid surface, usually defined as an analytical surface, and a deformable structure. Applications of this type of contact exist in the metal forming area where the punch and die surface geometries can be input as VDA surfaces which are treated as rigid. Another application is treating contact between rigid body occupant hyper-ellipsoids and deformable structures such as airbags and instrument panels. This option is particularly valuable in coupling with the rigid body occupant modelling codes MADYMO and CAL3D. Each contact definition must start with a *CONTACT_ card. The *CONTACT_1D is for modelling rebars in concrete structure. *CONTROL Options available in the *CONTROL section wither reset default global parameters, such as hourglass type, contact penalty scale factor, shell element formulation; or set parameters such as termination time. Page 4.4
Oasys LS-DYNA Environment: User Guide (Version 8.1) *DAMPING Defines damping either globally or by part identifier. *DATABASE This keyword with a combination of options can be used for controlling the ASCII and binary files output by LS-DYNA. This keyword defines the frequencies at which results are written to the various databases. *DEFINE This sections allows the user to define curves for loadings, constitutive behaviours, etc; boxes to limit the geometric extent of certain inputs; local coordinate systems; vectors; and orientation vectors specific to spring and throughout the input. For example, a coordinate system ID may be referenced on a *BOUNDARY_SPC_NODE card for a restraint, and load curves are used on the *AIRBAG cards. *DEFORMABLE_TO_RIGID This section allows the user to switch materials that are defined as deformable to rigid at the start of the analysis. This capability provides a cost efficient method for simulating events such as roll over events. While the vehicle is rotating the computation cost can be reduced significantly by switching deformable materials that are not expected to deform to rigid materials. Just before the vehicle comes in contact with ground, the analysis can be stopped and restarted with the materials switched back to deformable. *ELEMENT Solid, shell, thick shell, beam bar(truss), spring, lumped mass and seat belt elements can be set up in the input file. The elements used by LS-DYNA are all linear elements (i.e they have no mid-side nodes). As noted above elements belong to a part and have connectivity with other elements. The part has section properties, material properties and hourglass control properties. The connectivity is defined by the nodes on the element. Thus the element definition can be seen as a hierarchy as follows: *ELEMENT,eid,pid,nid1,nid2,nid3,nid4 *NODE,nid,x,y,z ... *PART,pid sid, mid, eosid,hgid *SECTION_SHELL,sid,elform,shrf,nip,propt,qr,icomp *MAT_ELASTIC,mid ro,e,pr,da,db *EOS,eosid *HOURGLASS,hgid In most cases the equation of state (*EOS) and hourglass (*HOURGLASS) options can be ignored. Page 4.5
Page 1: Oasys LS-DYNA Environment 8.1 VOLUM
Page 4 and 5: Oasys LS-DYNA Environment: User Gui
Page 70 and 71:
Oasys LS-DYNA Environment: User Gui
Page 72 and 73:
Page 74 and 75:
Page 76 and 77:
Page 78 and 79:
Page 80 and 81:
Page 82 and 83:
Page 84 and 85:
Page 86 and 87:
Page 88 and 89:
Page 90 and 91:
Page 92 and 93:
Page 94 and 95:
Page 96 and 97:
Page 98 and 99:
Page 100 and 101:
Page 102 and 103:
Page 104 and 105:
Page 106 and 107:
Page 108 and 109:
Page 110 and 111:
Page 112 and 113:
Page 114 and 115:
Page 116 and 117:
Page 118 and 119:
Page 120 and 121:
Page 122 and 123:
Page 124 and 125:
Page 126 and 127:
Page 128 and 129:
Page 130 and 131:
Page 132 and 133:
Page 134 and 135:
Page 136 and 137:
Page 138 and 139:
Page 140 and 141:
Page 142 and 143:
Page 144 and 145:
Page 146 and 147:
Page 148 and 149:
Page 150 and 151:
Page 152 and 153:
Page 154 and 155:
Page 156 and 157:
Page 158 and 159:
Page 160 and 161:
Page 162 and 163:
Page 164 and 165:
Page 166 and 167:
Page 168 and 169:
Page 170 and 171:
Page 172 and 173:
Page 174 and 175:
Page 176 and 177:
Page 178 and 179:
Page 180 and 181:
Page 182 and 183:
Page 184 and 185:
Page 186 and 187:
Page 188 and 189:
Page 190 and 191:
Page 192 and 193:
Page 194 and 195:
Page 196 and 197:
Page 198 and 199:
Page 200 and 201:
Page 202 and 203:
Page 204 and 205:
Page 206 and 207:
Page 208 and 209:
Page 210 and 211:
Page 212 and 213:
Page 214 and 215:
Page 216 and 217:
Page 218 and 219:
Page 220 and 221:
Page 222 and 223:
Page 224 and 225:
Page 226 and 227:
Page 228 and 229:
Page 230 and 231:
Page 232 and 233:
Page 234 and 235:
show all

Oasys LS-DYNA Environment 8.1 VOLUME 3 ... - Oasys Software

Create successful ePaper yourself

Delete template?

Save as template?