DEFORM-3D v6 Part 12 pot

276 ALE.DAT This triggers the steady state solution method to be used during the simulation. SPRING.INI This file allows the user to enable the usage of spring-loaded dies. SPRING2.INI This file allows the reversible spring loading direction to be specified. DEF_RSE.DAT This file allows to enable special features of the Rigid Super-Element scheme to be used during a simulation. 277 Appendix E: 2D to 3D Conversion Utility Purpose: Maps 2D geometry and all process variables from 2D database to 3D keyword file. How it works: 3D elements are created directly from 2D elements. In the case of axisymmetric simulations, the elements are revolved about an axis and for plane strain, the elements are extruded along an axis. For either case, the user has the option of Brick (8 node) or Tetrahedral (4 node) elements. If there are a large number of 2D element it is recommended to use manual remeshing to remesh the 2D object with 100-400 elements. After this, interpolate the state variable. Generate a database step with the new data. The new step will be negative, which you will specify in the conversion utility. How to run: Unix: From a command prompt, type M23 NT: Open a DOS command window and change to the problem directory (cd \deform3d\problem….). a. Run the M23.COM utility \deform3d\v51\M23.COM b. <Enter Problem ID without extension > (e.g. SPIKE) c. Enter 3d keyword file name [SPIKE_3.KEY] hit <CR> to accept default d Enter Step Number May be negative 278 e. Enter Object Number f. Enter number of nodes (4 nodes - tets recommended) g. Enter number of 3D planes to be created > h 3D elements are created by sweeping 2D plane about a common axis to create wedges i. Enter sweep angle > j. Total angle k. Enter node centerline tolerance l. Used to decide which nodes are centerline nodes - measurement should be made in 2D pre or post processor. m. Select variables to copy onto 3D mesh n. Defaults should be appropriate in most cases 279 Appendix F: Fracture with Element Deletion and Damage Softening Fracture within DEFORM-3D is now available. To implement this, only a few settings are required. The first setting that is required is the critical damage value for fracture. This is specified within the material properties window -> Advanced tab (See Figure 158). Within this window the damage criteria can be specified. By clicking the data window icon next to the criteria, a critical value can be input to the system (See Figure 159). The critical value to use is very dependent on the material being used, the processing methods to produce the material, deformation history, etc…. The recommended way in which to use the critical value is to either determine the absolute critical value for fracture based on a known process or to reduce the damage value of a given simulated process. Figure 158: The advanced material window. To implement only a critical damage value will enable damage softening. Damage softening is a method by which the flow stress of an element above this critical value will by reduced to a very low value. The advantage of this approach above element deletion is that the topology of part is maintained and is simple 281 Figure 160: Fracture settings window. Figure 161: Gear piercing case that is a good candidate for fracture study. 282 Figure 162: Beginning and near ending step of gear piercing with element deletion. Figure 163: Beginning and near ending step of gear piercing with damage softening. 283 Figure 164: Side-by-side comparison of piercing operations with element deletion and damage softening. 284 Appendix G: Rotating Work piece Simulations In many cases now there are new methods that are much more efficient. Please contact SFTC for more information. In this, special techniques for spinning work piece simulations are discussed. Among the applications that this would cover would be cross-rolling simulations (See Figure 165). Figure 165: Cross-rolling diagram. In the above case, there is a problem when the work piece rotates. The problem occurs due to the nature of updating nodal position based on integrating velocity over a time increment. The simple process of updating based on instantaneous velocity over a discrete time interval can cause an increase of the diameter of the work piece. As seen in Figure 166, all the nodal velocities are perpendicular to the radius where they are located. Thus, simply updating the coordinates based directly on their velocity will incur an increase in radius and in volume as well. 286 Examples: (1) spinning with a roller, if the user wants to fix the work piece and to rotate the roller (Figure 167) , and (2) thread rolling between two flat dies, if the user wants to fix the work piece and to rotate the two flat dies (Figure 165). How to Implement: If the following conditions are all met, DEFORM-3D will adopt the cylindrical coordinate for that object: Figure 167: Description of rotational axis definitions and angle definitions (derived from angular velocity values) for this case. 1. The first rotational axis and the second rotational axis are defined and they are apart from each other. 2. The translational movement is non-zero in the direction non-parallel to the second rotational axis. These values are defined in the Rotational Movement window. As seen in Figure 167, the first axis is the axis of the rotating tool and the second axis superimposes with the axis for the non-rotating work piece. The first rotational axis defines the rotational properties of the tool about it's own axis. If the tool does not spin about its own axis, as in a cross-rolling simulation, the axis center should be specified far from the work piece axis. The second rotational axis defines the rotational properties of tool about the axis of the work piece. 287 (For Example 2, the user needs to define the first rotational axis far away, say, 1.e6, but it is not used in calculation. In the DATA directory of DEFORM3D is an example file known as CROSS_ROLL.KEY. This is a simple cross-rolling example showing an example of how the tools can move about the work piece in order to simulate cross-rolling without rotating the work piece). As a note:  The initial position of this object is always used as a reference. The “Current Angle” in the Rotational Movement window should be zero at Step –1 and will be updated by the system at the end of every step or sub- step. The user should not change its value in a later step in the pre- processor without changing the position of this object accordingly.  The direction of the translational movement of this object is defined with respect to this reference position only. It will not be changed in a later step even the object rotates about the second rotational axis. The stroke will be updated in the same way. In the case of two rotational axes, when the axes are parallel, the angular velocities are defined as follows (seen in Figure 168):  2 = (r 1 /r 2 )  1 Figure 168: Two rotating bodies with parallel axes. [...]... applications within DEFORM-3D Theory - Anisotropy The associated flow rule with Hill'48 anisotropic yield criterion (Hill [2]) is used for consideration of initial texture property of sheet metal The flow potential for orthotropy which conserves three symmetry planes are written in terms of the stress ó as, f  2 1 T ó Pó  ó o   0 2 (1) with â 11 - â 12 -â P  2 13 0 0 0 - 12 - â 13 0 0 0 0 0... 0 0 0 - 12 - â 13 0 0 0 0 0 0 0 0 0 â 22 - â 23 0 - â 23 â 33 0 0 0 â 44 0 0 0 0 0 0 â 55 0 (2) 0 â 66 where ó T  ó xx , ó yy , ó zz , ó xy , ó yz , ó xz  and â 11  â 12  â13 ; â 22  12  â 23 ; â 33  â 13  â 23 (or 2 12  â11  â 22  â 33 ; 2â13  â11  â 22  â 33 ; 2â 23  â11  â 22  â 33 ) Therefore, six independent parameters â11 , â 22 , â 33 , â 44 , â 55 , â 66 need to be defined... locking or hourglassing To avoid these undesirable effects, the modified normal strain part, Equation (11), is assumed to be the same as Equation (12) in Equation (10) å h  å n  ås  å d  ås where (10) å n  u1,1 , u 2, 2 , u 3,3 ,0,0,0, å d  u1,1 , u 2 , 2 , u 3,3 ,0,0,0 , u i , j  u i , j  iju k , k /3 (11) (12) (13) Here, the repeated index is used to denote the summation Possible shear locking... Line 6: RADCTR, OMECTR (2 real numbers) PLEASE NOTE: The meaning of OMECTR is different than that in Option 3: If OMECTR is set to 1.e +12, the rotating direction is specified, while the magnitude of each nodal velocity is the result of simulation If OMECTR is set to 0, the part of work piece is fixed Line 7: XMIN, XMAX , VXMIN, VXMAX (4 real numbers; optional) VXMIN is the speed of the left bounding point,... region of the spinning object, this method cannot be used Also, in order for the AXIS.DAT file to work properly in the latest version of DEFORM-3D, a file named DEF_RSE.DAT containing a single 0 should also exist in the working directory 292 Appendix H: Sheet Forming in DEFORM-3D Due to advantages in modeling thin structures, the membrane or shell element formulations are very popular in the simulation... cos  Figure 169: A rotating body with two non-parallel axes G2 Spinning Work piece There are some features used to model the deformation of a rotating work piece with DEFORM-3D They are under testing and have yet been officially added to DEFORM-3D However, the user may activate these features when necessary by defining a data file "AXIS.DAT" in the working directory of a simulation The options and contents... 1 Enforces rotational update of nodal coordinates (This solves the problem described above with the volume increase) Mode = 3 Part of object KOBJAX (defined below) is forced to spin about an axis (defined by RAXIS) in addition to enforcement of rotational updating Mode = 5 Part of object KOBJAX (defined below) is forced to spin 289 about an axis (defined by RAXIS) in addition to enforcement of rotational... implementation of Hill’48 yield criterion is outlined below The additive decomposition of strain-rate into elastic and plastic parts is employed together with the normality rule,    å  åe  åp ,   ó  Cå e , f  (4) )  ëa ó where the superscripts e and p represent the elastic and plastic parts,  respectively C is the elasticity tensor, ë is the plastic strain-rate multiplier and a is the flow vector... Line 6: RADCTR, OMECTR (2 real numbers) PLEASE NOTE: The meaning of OMECTR is different than that in Option 3: If OMECTR is set to 1.e +12, the rotating direction is specified, while the magnitude of each nodal velocity is the result of simulation If OMECTR is set to 0, the part of work piece is fixed Line 7: XMIN, XMAX , VXMIN, VXMAX (4 real numbers; optional) VXMIN is the speed of the left bounding point,... and diagonal (DD) directions are compared with the measurements in Table 2 The measured data is average values of three participations (B1E-02, B1E-03 and B1E-04) in NUMESHEET’99 benchmark test Figure 174: FE model for cylindrical cup drawing Punch force (kN) 160 Measured Simulation 120 80 40 0 0 30 60 90 Punch travel (mm) Figure 175: Punch force vs stroke curve Measured point Measure d Simulation 299 . where   xzyzxyzzyyxx T ó,ó,ó,ó,ó,óó and 1 3121 1 âââ  ; 2 3122 2 âââ  ; 231333 âââ  (or 33221 112 âââ2â  ; 33221113 âââ2â  ; 3322 1123 âââ2â  ). Therefore, six independent parameters. The flow potential for orthotropy which conserves three symmetry planes are written in terms of the stress ó as,   0ó 2 1 f 2 oT  Póó . (1) with 66 55 44 332313 232 212 1 3121 1 â00000 0â0000 00â000 000ââ-â- 000â-ââ- 000â-â-â 2P . If OMECTR is set to 1.e +12, the rotating direction is specified, while the magnitude of each nodal velocity is the result of simulation. If OMECTR is set to 0, the part of work piece is fixed.