3. Operands#
Here, we draw attention to a few tricky aspects of using POST_USURE.
The result of POST_USURE does not depend on the final mechanical state of the calculation but on the entire history of the shocks. It is therefore very important to take into account all the calculation moments, i.e. not to ask for selective archiving in DYNA_TRAN_MODAL.
The result of POST_USURE is very sensitive to the calculation parameters, in particular to the richness of the modal base, and to the time step. It is therefore strongly recommended to test different modal bases (increasingly rich) and different time steps (smaller and smaller). For example, for the time step, we can test different values spaced apart by a factor of 10, then 2, in order to determine a range of time steps over which the result is stable.
In the case of a vibration calculation, we can have a result that is not representative of real wear if the experiment is not long enough. Likewise, in the case of randomly generated excitations, it is advisable to perform several draws before drawing sizing conclusions.
3.1. Case PUIS_USURE or RESU_GENE#
3.1.1. Operand PUIS_USURE#
♦ PUIS_USURE = or
The wear power is:
resulting from the result of a transitory calculation by modal recombination, produced by the operator DYNA_TRAN_MODAL [U4.53.21] (following operands),
or given by the user who then uses the PUIS_USURE operand.
3.1.2. Operand RESU_GENE#
♦ RESU_GENE = TG
Result of a transient calculation by modal recombination, produced by the operator DYNA_TRAN_MODAL [U4.53.21].
3.1.3. Operand GROUP _ NO#
Definition of the shock node to be post-treated.
3.1.4. Operand INST_INIT#
◊ INST_INIT = t0
Start time of signal averaging (cf. [§4]).
(t0 = 0. value by default).
3.1.5. Operand INST_FIN#
◊ INST_FIN = t1
The moment at which the averaging of the signals ends.
3.1.6. Operand NB_BLOC#
◊ NB_BLOC = nb
Number of time blocks for dividing the interval [t0, t1] for the averaging of signals (1 by default).
3.2. Case TUBE_NEUF#
To treat the wear of the control clusters, the user can take into account the change from one tube to a new one by entering the keyword TUBE_NEUF = “OUI”
3.2.1. Operand TUBE_NEUF#
◊ TUBE_NEUF = 'OUI'
If the user enters this keyword, the operator changes the wear values of the tube (V_ USUR_TUBE, P_, P_ USUR_TUBE, V_ USUR_TUBE_SECT, P_ USUR_TUBE_SECT, V_ USUR_TUBE_CUMU = 0) in the table from POST_USURE for the moments after the time the new tube was loaded.
3.2.2. Operand TABL_USURE#
♦ TABL_USURE = treasure
If the user enters the keyword TUBE_NEUF = “OUI”, the name of the table to be updated must be entered. This table is the same as the one that is output from the operator. The moment when the tube was changed by a new tube is entered in the keyword INST.
3.3. Law of usury “ARCHARD”#
3.3.1. Operand LOI_USURE#
♦ LOI_USURE = 'ARCHARD'
Define the law of wear in order to calculate the worn volume.
The wear coefficient of Archard’s law is provided by the user or taken from a database.
3.3.2. Keyword MOBILE#
♦ MOBILE
Definition of the wear coefficient of the mobile.
3.3.2.1. Operand COEF_USURE#
♦ COEF_USURE = k_t
Value of the wear coefficient of the mobile.
3.3.3. Keyword OBSTACLE#
◊ OBSTACLE
Definition of the wear coefficient of the obstacle.
3.3.3.1. Operand COEF_USURE#
♦ COEF_USURE = k_o
Value of the wear coefficient of the obstacle.
3.3.4. Operand MATER_USURE#
♦ MATER_USURE = 'mat1_mat2'
Retrieving the coefficients in a database:
mat1: being the material of the cluster or the tube (the mobile),
mat2: being the material of the obstacle.
3.3.5. Operand USURE_OBST#
◊ USURE_OBST =/'OUI' [DEFAUT]
Indicates whether to take into account the wear and tear of the obstacle.
3.3.6. Operand SECTEUR#
◊ SECTEUR =
Definition of the various quantities required to cut the game figure into angular sectors.
3.3.6.1. Keyword COEF_USURE_MOBILE#
♦ COEF_USURE_MOBILE = K_t [R]
Definition of the wear coefficient of the mobile in the sense of Archard’s law for the sector.
3.3.6.2. Keyword COEF_USURE_OBST#
♦ COEF_USURE_OBST = K_o [R]
Definition of the obstacle wear coefficient in the sense of Archard’s law for the sector.
3.3.6.3. Keyword ANGL_INIT#
◊ ANGL_INIT = ang_i [R]
Definition of the initial angular value of the sector.
3.3.6.4. Keyword ANGL_FIN#
♦ ANGL_FIN = ang_f [R]
Definition of the final angular value of the sector.
3.4. Law of usury “KWU_EPRI”#
3.4.1. Operand LOI_USURE#
♦ LOI_USURE = 'KWU_EPRI'
Define the law of wear in order to calculate the worn volume.
3.4.2. Keyword MOBILE#
♦ MOBILE
Definition of the wear coefficient of the mobile (provided by the user or taken from the database).
3.4.2.1. Operands COEF_ *#
♦ COEF_FNOR = k1_t
Definition of the dimensional correction coefficient in the case of pure impacts.
♦ COEF_VTAN = k2_t
Definition of the dimensional correction coefficient in the case of slips.
♦ COEF_USURE = k3_t
Definition of the reference wear coefficient.
◊ COEF_K =/k_t
/5. [DEFAUT]
Definition of the constant.
◊ COEF_C =/c_t
/10. [DEFAUT]
Definition of the constant.
3.4.3. Keyword OBSTACLE#
◊ OBSTACLE
Definition of the obstacle wear coefficient (provided by the user or taken from the database).
3.4.3.1. Operands COEF_ *#
♦ COEF_FNOR = k1_o
Definition of the dimensional correction coefficient in the case of pure impacts.
♦ COEF_VTAN = k2_o
Definition of the dimensional correction coefficient in the case of slips.
♦ COEF_USURE = k3_o
Definition of the reference wear coefficient.
◊ COEF_K =/k_o
/5. [DEFAUT]
Definition of the constant.
◊ COEF_C =/c_o
/10. [DEFAUT]
Definition of the constant.
3.4.4. Operand MATER_USURE#
♦ MATER_USURE = 'mat1_mat2'
Retrieving coefficients from a database=
mat1 = being the material of the cluster or the tube (the mobile),
mat2 = being the material of the obstacle.
3.4.5. Operand USURE_OBST#
◊ USURE_OBST =/'OUI' [DEFAUT]
Indicates whether to take into account the wear and tear of the obstacle.
3.4.6. Operands FNOR_MAXI/VTAN_MAXI#
◊ FNOR_MAXI = fn
Definition of the maximum normal force to be taken into account for the distribution of the 5 classes for the law of usury KWU_EPRI.
◊ VTAN_MAXI = vg
Definition of the maximum sliding speed to be taken into account for the distribution of the 5 classes for wear law KWU_EPRI.
3.5. Law of usury “EDF_MZ”#
3.5.1. Operand LOI_USURE#
♦ LOI_USURE = 'EDF_MZ'
Define the law of wear in order to calculate the worn volume.
3.5.2. Keyword MOBILE#
♦ MOBILE
Definition of the wear coefficient of the mobile (provided by the user or taken from the database).
3.5.2.1. Operands COEF_ *#
♦ COEF_USURE =/a_t
/1.E-13 [DEFAUT]
Definition of the wear coefficient A.
◊ COEF_B =/b_t
/1.2 [DEFAUT]
Definition of the exponent of wear power b.
◊ COEF_N =/n_t
/2.44E-08 [DEFAUT]
Definition of downturn rate n.
◊ COEF_S =/S_t
/1.14E-16 [DEFAUT]
Threshold definition S.
3.5.3. Keyword OBSTACLE#
◊ OBSTACLE
Definition of the obstacle wear coefficient (provided by the user or taken from the database).
3.5.3.1. Operands COEF_ *#
♦ COEF_USURE =/a_o
/1.E-13 [DEFAUT]
Definition of the wear coefficient A.
◊ COEF_B =/b_o
/1.2 [DEFAUT]
Definition of the exponent of wear power b.
◊ COEF_N =/n_o
/2.44E-08 [DEFAUT]
Definition of downturn rate n.
◊ COEF_S =/s_o
/1.14E-16 [DEFAUT]
Threshold definition S.
3.5.4. Operand MATER_USURE#
♦ MATER_USURE = 'mat1_mat2'
Retrieving coefficients from a database=
mat1 = being the material of the cluster or the tube (the mobile),
mat2 = being the material of the obstacle.
3.5.5. Operand USURE_OBST#
◊ USURE_OBST =/'OUI' [DEFAUT]
Indicates whether to take into account the wear and tear of the obstacle.
3.6. Operand CONTACT#
♦ CONTACT = geom
Definition of contact geometry.
Depending on the type of contact, different geometric relationships between the worn volumes and the worn depths.
3.6.1. Operand CONTACT = “GRAPPE_ALESAGE”#
The cluster is centered in a bore. The wear trace has a lunula-shaped section. The spent volume is returned to a worn area in a section.
3.6.2. Operand CONTACT = “GRAPPE_1_ENCO”#
The cluster is centered in relation to the obstacle.
The guide map is formed by a notch. The spent volume is returned to a worn area in a section.
The coefficients are based both on the experimental results and on those of the feedback. They only apply to control clusters.
3.6.3. Operand CONTACT = “GRAPPE_2_ENCO”#
The cluster is centered in relation to the obstacle.
The guide map is formed by two diametrically opposed notches. The spent volume is returned to a worn area in a section.
The coefficients are based both on the experimental results and on those of the feedback. They only apply to control clusters.
3.6.4. Operand CONTACT = “TUBE_BAV”#
Case 1:
The tube is presented vertically, the bar impacts perpendicular to the tube, it is assumed that the bar does not wear out.
Case 2:
The bar is inclined (operand ANGL_INCLI) with respect to the tube, the bar impacts perpendicular to the tube, it is assumed that the bar does not wear out.
Case 3:
The tube is presented vertically, the bar impacts perpendicular to the tube, the wear of the bar is taken into account.
Case 4:
The bar is inclined (operand ANGL_INCLI) with respect to the tube, the bar impacts perpendicular to the tube, the wear of the bar is taken into account.
3.6.5. Operand CONTACT = “TUBE_ALESAGE”#
Case 1:
The tube is perfectly centered in a bore animated by a pure orbital movement and wears uniformly over the entire periphery in contact with the obstacle.
Case 2:
The tube is centered in a bore animated by an elliptical impact-sliding movement which leads to the formation of diametrically opposed cylindrical wear marks on the tube and having a lunula-shaped cross section.
Case 3:
The tube, animated by an impact-sliding movement, this time has an inclination with respect to the support (operand ANGL_INCLI). Two symmetrical V-shaped wear marks are obtained on the tube.
3.6.6. Operand CONTACT = “TUBE_3_ENCO”#
Case 1:
The initial contact is made against an edge of one of the isthmus of a trifoliate bore. It is assumed that the tube is perfectly centered in relation to its obstacle. The sign of wear and tear does not extend to the entire isthmus. The wear and tear of the obstacle is not taken into account.
Case 2:
Same hypotheses as for case 1 except for the position of the tube in relation to the obstacle. This time it is assumed that the tube has an angle of inclination (operand ANGL_INCLI).
3.6.7. Operand CONTACT = “TUBE_4_ENCO”#
Case 1:
The initial contact is made against an edge of one of the isthmus of the quadrifoliate bore. It is assumed that the tube is perfectly centered in relation to its obstacle. The sign of wear and tear does not extend to the entire isthmus. The wear and tear of the obstacle is not taken into account.
Case 2:
Same hypotheses as for case 1 except for the position of the tube in relation to the obstacle. This time it is assumed that the tube has an angle of inclination (operand ANGL_INCLI).
3.6.8. Operand CONTACT = “TUBE_TUBE”#
Following the rupture of a plugged tube, there may be contact between this tube and one of its neighbors. The wear of the two tubes by accommodation of the surfaces in contact leads to the creation of two flat surfaces.
3.7. Obstacle description#
3.7.1. Operand RAYON_MOBILE#
♦ RAYON_MOBILE = r_t
Definition of the mobile radius (mandatory parameter).
3.7.2. Operand RAYON_OBST#
♦ RAYON_OBST = r_o
Definition of the radius of the obstacle (mandatory parameter if the wear of the obstacle is taken into account).
3.7.3. Operand LARGEUR_OBST#
♦ LARGEUR_OBST = l_o
Definition of the width of the obstacle (mandatory parameter for TUBE_ * operands).
3.7.4. Operand ANGL_INCLI#
◊ ANGL_INCLI = angle
Definition of the angle of the mobile/obstacle inclination (optional parameter = the value 0. is taken by default).
3.7.5. Operand ANGL_ISTHME#
♦ ANGL_ISTHME = English
Definition of the angle of the isthmus of the contact geometry (mandatory parameter for operands TUBE_3_ENCO and TUBE_4_ENCO).
3.8. Definition of analysis moments#
3.8.1. Case PUIS_USURE or RESU_GENE#
3.8.1.1. Operands INST/LIST_INST/COEF_INST#
♦ INST = l_inst
Definition of calculation times in the form of a list of values.
♦ LIST_INST = the link
Definition of calculation times in the form of a listr8 concept.
◊ COEF_INST = key
The times given are to be multiplied by a given coef coefficient, which makes it possible to easily switch from SI units to natural units for a calculation of wear (the month of the year).
3.8.2. Case TUBE_NEUF#
If TUBE_NEUF = “OUI”, you can enter the loading time.
3.8.2.1. Operand INST#
◊ INST = inst
Instant loading of a new tube.
The wear values of the tube (V_ USUR_TUBE, P_ USUR_TUBE, P_, V_, V_, V_, V_, V_, V_, V_, V_ USUR_TUBE_SECT, P_ USUR_TUBE_SECT, V_ USUR_TUBE_CUMU) are set to 0 for the moments after the time the new tube is loaded. By default, the wear values from the last moment of the table are set to 0 if TUBE_NEUF = “OUI”.
3.9. Operand ETAT_INIT#
3.9.1. Keyword TABL_USURE#
♦ TABL_USURE = true [table_saster]
Definition of the table you want to update.
3.9.2. Keyword INST_INIT#
◊ INST_INIT = tt [R]
Definition of the moment at which you want to update the table.
3.10. Operands TITRE/INFO#
◊ TITRE = 'mytitle'
Title we want to give to the result [U4.03.01].
◊ INFO =/1
/2
Print Level
1 |
no printing. |
2 |
impression of the volumes and depths of wear at the specified times |
3.11. Table produced#
The POST_USURE command generates a table-like concept, the content of which is:
INST: |
moments at which the user wants to know the volume and depth of wear, |
V_usur_tube: |
volume worn out at the pipe level (for each moment specified by the user), |
V_usur_obst: |
volume worn out at the obstacle level (for each moment specified by the user), |
P_usur_tube: |
depth of wear at the level of the tube (for each moment specified by the user). |
The IMPR_TABLE [U4.91.03] command allows you to print the results.