force modify element_like field
Allows you to modify of the field object.
Format:
force modify element_like field |
|---|
field_name = | model_1.field1 |
new_field_name = | FIELD__1 |
Adams_id = | 1 |
comments = | comment1 |
i_marker_name = | marker_1 |
j_marker_name = | marker_2 |
translation_at_preload = | matrix of 3 values |
rotation_at_preload = | matrix of 3 values |
force_preload = | matrix of 3 values |
torque_preload = | matrix of 3 values |
stiffness_matrix = | matrix of 6x6 values |
damping_ratio = | real_number |
matrix_of_damping_terms = | 6x6 matrix of real values |
user_function = | real number |
Example:
force modify element_like field & |
|---|
field_name = | model_1.field1 & |
new_field_name = | FIELD__1 & |
Adams_id = | 1 & |
comments = | comment1 & |
i_marker_name = | marker_1 & |
j_marker_name = | marker_2 & |
translation_at_preload = | 0.5, 0.2, 0.5 & |
rotation_at_preload = | 0.5, 0.2, 0.4 & |
force_preload = | 0.2, 0.1, 0.5 & |
torque_preload = | 0.4, 0.1, 0.8 |
Description:
Parameter | Value Type | Description |
|---|
field_name | An Existing Field | Specifies the field to modify. You use this parameter to identify the existing field to affect with this command. |
new_field_name | A New Field | Specifies the name of the new field. You may use this name later to refer to this field. |
Adams_id | Integer | Specifies an integer used to identify this element in the Adams data file. |
comments | String | Specifies comments for the object being created or modified. |
i_marker_name | An Existing Marker | Specifies a marker on the first of two parts connected by this force element. Adams View connects this element to one part at the I marker and to the other at the J marker. |
j_marker_name | An Existing Marker | Specifies a marker on the second of two parts connected by this force element. Adams View connects this element to one part at the I marker and to the other at the J marker. |
translation_at_preload | Length | Defines a vector of reference translations. |
rotation_at_preload | Angle | Defines a vector of reference rotations. |
force_preload | Force | Specifies a vector of three constant terms for the bushing force. These terms are the constant force components along the x-axis, the y-axis, and the z-axis of the J marker. |
torque_preload | Torque | Defines a vector of reference torques at the angular displacement specified in the parameter ROTATION_AT_PRELOAD. The values r1, r2, r3 are the torque components about the x-axis, the y-axis, and the z axis of the J marker. |
stiffness_matrix | Real | Specifies a six-by-six matrix of stiffness coefficients. |
damping_ratio | Real | Specifies the ratio of MATRIX_OF_DAMPING to STIFFNESS_MATRIX. If you input DAMPING_RATIO, Adams multiplies STIFFNESS_MATRIX by this parameter to obtain MATRIX_OF_DAMPING_TERMS. |
matrix_of_damping_terms | Real | Specifies a six-by-six matrix of viscous damping coefficients. |
user_function | Real | Specifies up to 30 values for Adams to pass to a user written subroutine. See the Adams User's Manual for information on writing user-written subroutines. |
FORMULATION | | By default, the LINEAR option is used. The LINEAR option matches the behavior of previous releases. The NONLINEAR option forces Adams Solver to add a geometric stiffness term; this option is useful if the FIELD is being used to model beams. Default: LINEAR |
LENGTH_TOL | | When using FORMULATION=NONLINEAR, the geometric stiffness uses the larger of the current length and length tolerance. Default: 1.e-05 |
Extended Definition:
1. A field is a translational and a rotational action-reaction force applied between two markers. If you want to specify a linear field, use the arguments in the command to specify constants for the six-by-six stiffness matrix, a six-element reference length vector, and a six-by-six damping matrix. The stiffness and damping matrices must be positive semi definite, but need not be symmetric. If you want to specify a nonlinear field, use the Adams user-written subroutine FIESUB to define the three force components and the three torque components and use the Adams View parameter USER_FUNCTION=r1[,...,r30] to pass constants to FIESUB. The following constitutive equations define how Adams uses the data you input for a linear field to apply a force and a torque to the I marker depending on the displacement and velocity of the I marker relative to the J marker. Adams applies a force of equal magnitude and opposite direction to the J marker. The torque on the J marker has two components. The first component is equal and opposite to the torque on the I marker. The second component is due to the couple generated by the equal and opposite forces acting at the I and J markers.
[Fx] [K11 K12 K13 K14 K15 K16] [x-xo]
[Fy] [K21 K22 K23 K24 K25 K26] [y-yo]
[Fz] = - [K31 K32 K33 K34 K35 K36] [z-zo]
[Tx] [K41 K42 K43 K44 K45 K46] [a-ao]
[Ty] [K51 K52 K53 K54 K55 K56] [b-bo]
[Tz] [K61 K62 K63 K64 K65 K66] [c-co]
[C11 C12 C13 C14 C15 C16] [Vx] [F1]
[C21 C22 C23 C24 C25 C26] [Vy] [F2]
- [C31 C32 C33 C34 C35 C36] [Vz] + [F3]
[C41 C42 C43 C44 C45 C46] [Wx] [T1]
[C51 C52 C53 C54 C55 C56] [Wy] [T2]
[C61 C62 C63 C64 C65 C66] [Wz] [T3]
For a nonlinear field, you define the following constitutive equations in the FIESUB
subroutine:
Fx = f (x,y,z,a,b,c,Vx,Vy,Vz,Wx,Wy,Wz)
1
Fy = f (x,y,z,a,b,c,Vx,Vy,Vz,Wx,Wy,Wz)
2
Fz = f (x,y,z,a,b,c,Vx,Vy,Vz,Wx,Wy,Wz)
3
Tx = f (x,y,z,a,b,c,Vx,Vy,Vz,Wx,Wy,Wz)
4
Ty = f (x,y,z,a,b,c,Vx,Vy,Vz,Wx,Wy,Wz)
5
Tz = f (x,y,z,a,b,c,Vx,Vy,Vz,Wx,Wy,Wz)
6
Adams applies the defined forces and torques at the I marker. In the linear and the nonlinear equations, Fx, Fy, and Fz are the three translational force measure numbers, and Tx, Ty, and Tz are the three rotational force measure numbers associated with unit vectors directed along the x-axis, the y-axis, and the z-axis of the coordinte system fixed in the J marker reference frame; K is the stiffness matrix; xo,yo, zo, ao, bo, and co are the free lengths; x, y, z, a, b, and c are the translational and the rotational displacements of the I marker with respect to the J marker expressed in the reference frame of the J marker; Vx, Vy, Vz, Wx, Wy, and Wz are the scalar time derivatives of x, y, z, a, b, and c, respectively; C is the damping matrix; and F1, F2, F3, T1, T2, and T3 are the translational and the rotational pre-tensions. All variables and time derivatives are computed in the J marker coordinate system.
2. You may identify a field by typing its name or by picking it from the screen.
If the field is not visible on the screen, you must type the name. You may also find it convenient to type the name even if the field is displayed. If you created the field by reading an Adams data set file, the field name is 'FIE'. If you created the field during preprocessing, you gave it a name at that time. If a field is available by default, you may identify it by entering its name only. If it is not, you must enter its full name. To identify a field under a different model, for instance, you may need to enter the model name as well. For example, you may specify field 'fld1' from model 'robot' by entering ".robot.fld1". If you type a "?", Adams View will list the fields available by default. You must separate multiple field names by commas. If the field is visible in one of your views, you may identify it by picking on any of the graphics associated with it. You need not separate multiple field picks by commas..
3. Normally, entity names are composed of alphabetic, numeric, or '_' (underscore) characters, and start with an alphabetic or '_' character. They may be any length.
For more information, see
Using Extended Names.
By enclosing the name in double quotes, you may use other printable characters, or start the name with a numeral. If a name contains characters, or starts with a numeral, you must always quote the name when entering it. Note that you can specify the parentage of an entity (e.g. what part "owns" a marker or a geometry element) when you CREATE it by changing the name. If you enter just the
entity name, then the default parent will be assigned by Adams View. If you type in the full name, then you may over ride the default parent. In most cases, when creating an entity, Adams View will provide a default name. The default name that Adams View provides will specify the parentage that it has assumed. You may, or course, delete this name and use your own. The form of a full name is:
"...._NAME.GRAND_PARENT_NAME.PARENT_NAME.ENTITY_NAME"
The number of levels used varies from case to case and the parentage must exist before an entity can be assigned to it.
4. When you use the FILE Adams_DATA_SET WRITE command, Adams View writes an Adams data file for your model. Adams requires that each modeling element be identified by a unique integer identifier. If you use this parameter to specify a non-zero identifier, Adams View will use it in the corresponding statement in the Adams data file. You may also enter zero as an identifier, either explicitly or by default. The next time you write an Adams file, Adams View will replace the zero with a unique, internally generated identifier. Adams View will permanently store this identifier with the element just as if you had entered it yourself. Normally, you would let all identifiers default to zero, and Adams View would generate the identifiers for you. You are never required to enter a non-zero identifier. You only need to specify it if, for some reason, you wish to control the Adams file output.
5. When an Adams Solver data file (.adm) is read into Adams View, all comments associated with a statement (from the end of the previous statement through the end of the current statement) are stored with the object. Comments in the data file can be associated with model. These comments must follow the title statement and be followed by the comment 'END OF MODEL COMMENTS'. This string must be uppercase. When an Adams Solver data file is written, the comments for an object are written before the statement corresponding to the object.
6. The ‘translation_at-preload’ parameter defines a vector of reference translations. This is the nominal position of the I marker with respect to the J marker, resolved in the J marker coordinate system. The values r1, r2, r3 are the x, y, and z translational components of the translation. Adams uses the translational distance specified in TRANSLATION_AT_PRELOAD to calculate the resultant torque on the J marker. If the reference force is zero, TRANSLATION_AT_PRELOAD is the same as the free translation.
7. The rotation_at_preload parameter defines a vector of reference rotations. This defines the nominal orientation of the I marker with respect to the J marker, resolved in the J marker coordinate system. The terms r1, r2, r3 the x, y, and z rotational components. Adams uses the angular displacements specified in ROTATION_AT_PRELOAD to calculate the resultant torque on the J marker. If the reference force is zero, ROTATION_AT_PRELOAD is the same as the free rotation.entries.
8. The stiffness_matrix parameter specifies a six-by-six matrix of stiffness coefficients. The following matrix shows the values to input:
[r01 r07 r13 r19 r25 r31]
[r02 r08 r14 r20 r26 r32]
[r03 r09 r15 r21 r27 r33]
[r04 r10 r16 r22 r28 r34]
[r05 r11 r17 r23 r29 r35]
[r06 r12 r18 r24 r30 r36]
Enter the elements by columns from top to bottom, then from left to right. If you do not use both CRATIO and KMATRIX, Adams cannot calculate the damping coefficients; in that case, you must define CMATRIX if you want to include damping coefficients in the calculation of the field forces. KMATRIX defaults to a matrix with thirtysix zero entries.
9. The matrix_of_damping_terms parameter specifies a six-by-six matrix of viscous damping coefficients. The following matrix shows the values to input:
[r01 r07 r13 r19 r25 r31]
[r02 r08 r14 r20 r26 r32]
[r03 r09 r15 r21r27 r33]
[r04 r10 r16 r22 r28 r34]
[r05 r11 r17 r23 r29 r35]
[r06 r12 r18 r24 r30 r36]
Enter the elements by columns from top to bottom, then from left to right. If you do not use either CMATRIX or both CRATIO and KMATRIX, CMATRIX defaults to a matrix with thirty-six zero entries.
Cautions:
1. Adams View will not allow you to have two fields with the same full name, so you must provide a unique name.
2. Do not use the ‘damping_ratio’ parameter without also using STIFFNESS_MATRIX.
Tips:
■If you type a "?", Adams View will list the gravity fields available by default.