Contact Force on certain locations in ADAMS

[khashpj]

Hi

I have a question about measuring contact forces in ADAMS
Imagine we have box falling on a plate. When I measure the contact force (clicking on Measure for Contact) it gives me one value for contact force (say Fy for example) what if I want to find out the contact force on a certain location on the box during impact?
I have tried putting markers there and measuring Force on point but the value remains 0 during whole process.
Thanks

Here is a picture to clarify my question

http://s28.postimg.org/rvyanax8t/question.jpg

[/url]]

 

[GregLocock]

I'm not sure but I think :

your contact force statement measures the force in the constraint. since there is no constraint at your new marker position, there is no force to measure.



Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[khashpj]

Hi Greg

In that case the amount of force that has been measured here is exactly at which constraint? Is it at the revolving joints? or on the whole contact area?

 

[GregLocock]

The contact force is measured at the contact marker. If you export your model as an adm file and post it here I'll have a look.




Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[khashpj]

I would really appreciate it.
I will attach it tomorrow morning. (I just have access to Adams at school)
Thanks

 

[khashpj]

In that case I would need to define or move the contact marker, which I would appreciate it if you could tell me how to do so

 

[khashpj]

Here is the adm file
Thanks in advance

!
!-------------------------- Default Units for Model ---------------------------!
!
!
defaults units &
length = meter &
angle = deg &
force = newton &
mass = kg &
time = sec
!
defaults units &
coordinate_system_type = cartesian &
orientation_type = body313
!
!------------------------ Default Attributes for Model ------------------------!
!
!
defaults attributes &
inheritance = bottom_up &
icon_visibility = on &
grid_visibility = off &
size_of_icons = 5.0E-002 &
spacing_for_grid = 1.0
!
!------------------------------ Adams/View Model ------------------------------!
!
!
model create &
model_name = ramp
!
view erase
!
!--------------------------------- Materials ----------------------------------!
!
!
material create &
material_name = .ramp.steel &
adams_id = 1 &
youngs_modulus = 2.07E+011 &
poissons_ratio = 0.29 &
density = 7801.0
!
!-------------------------------- Rigid Parts ---------------------------------!
!
! Create parts and their dependent markers and graphics
!
!----------------------------------- ground -----------------------------------!
!
!
! ****** Ground Part ******
!
defaults model &
part_name = ground
!
defaults coordinate_system &
default_coordinate_system = .ramp.ground
!
! ****** Markers for current part ******
!
marker create &
marker_name = .ramp.ground.MARKER_1 &
adams_id = 1 &
location = 0.0, 0.0, 0.0 &
orientation = 45.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.ground.MARKER_7 &
adams_id = 7 &
location = -3.5355339059E-002, 3.5355339059E-002, 1.38 &
orientation = 0.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.ground.MARKER_9 &
adams_id = 9 &
location = -3.5355339059E-002, 3.5355339059E-002, 0.0 &
orientation = 0.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.ground.MARKER_11 &
adams_id = 11 &
location = -0.4, -5.0E-002, 0.0 &
orientation = 0.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.ground.MARKER_13 &
adams_id = 13 &
location = -0.4, -5.0E-002, 1.38 &
orientation = 0.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.ground.MARKER_15 &
adams_id = 15 &
location = 0.0, -5.0E-002, 1.38 &
orientation = 0.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.ground.MARKER_17 &
adams_id = 17 &
location = 0.0, -5.0E-002, 0.0 &
orientation = 0.0d, 0.0d, 0.0d
!
! ****** Graphics for current part ******
!
geometry create shape block &
block_name = .ramp.ground.BOX_1 &
adams_id = 1 &
corner_marker = .ramp.ground.MARKER_1 &
diag_corner_coords = 0.259, 5.0E-002, 1.38
!
!----------------------------------- PART_2 -----------------------------------!
!
!
defaults coordinate_system &
default_coordinate_system = .ramp.ground
!
part create rigid_body name_and_position &
part_name = .ramp.PART_2 &
adams_id = 2 &
location = 0.0, 0.0, 0.0 &
orientation = 0.0d, 0.0d, 0.0d
!
defaults coordinate_system &
default_coordinate_system = .ramp.PART_2
!
! ****** Markers for current part ******
!
marker create &
marker_name = .ramp.PART_2.MARKER_2 &
adams_id = 2 &
location = -0.4, -5.0E-002, 0.0 &
orientation = 0.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.PART_2.cm &
adams_id = 18 &
location = -0.2, -2.5E-002, 0.69 &
orientation = 90.0d, 180.0d, 0.0d
!
marker create &
marker_name = .ramp.PART_2.MARKER_10 &
adams_id = 10 &
location = -0.4, -5.0E-002, 0.0 &
orientation = 0.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.PART_2.MARKER_12 &
adams_id = 12 &
location = -0.4, -5.0E-002, 1.38 &
orientation = 0.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.PART_2.MARKER_14 &
adams_id = 14 &
location = 0.0, -5.0E-002, 1.38 &
orientation = 0.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.PART_2.MARKER_16 &
adams_id = 16 &
location = 0.0, -5.0E-002, 0.0 &
orientation = 0.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.PART_2.MARKER_20 &
adams_id = 20 &
location = -0.4, 0.0, 0.0 &
orientation = 0.0d, 0.0d, 0.0d
!
part create rigid_body mass_properties &
part_name = .ramp.PART_2 &
material_type = .ramp.steel
!
! ****** Graphics for current part ******
!
geometry create shape block &
block_name = .ramp.PART_2.BOX_2 &
adams_id = 2 &
corner_marker = .ramp.PART_2.MARKER_2 &
diag_corner_coords = 0.4, 5.0E-002, 1.38
!
part attributes &
part_name = .ramp.PART_2 &
color = CYAN &
name_visibility = off
!
!----------------------------------- PART_3 -----------------------------------!
!
!
defaults coordinate_system &
default_coordinate_system = .ramp.ground
!
part create rigid_body name_and_position &
part_name = .ramp.PART_3 &
adams_id = 3 &
location = 0.0, 0.0, 0.0 &
orientation = 45.0d, 0.0d, 0.0d
!
defaults coordinate_system &
default_coordinate_system = .ramp.PART_3
!
! ****** Markers for current part ******
!
marker create &
marker_name = .ramp.PART_3.MARKER_3 &
adams_id = 3 &
location = 0.0, 5.0E-002, 0.0 &
orientation = 0.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.PART_3.cm &
adams_id = 19 &
location = 0.1295, 0.229, 0.69 &
orientation = 0.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.PART_3.MARKER_4 &
adams_id = 4 &
location = 0.0, 0.408, 1.38 &
orientation = 0.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.PART_3.CG &
adams_id = 5 &
location = 0.1410678028, 0.2124855877, 0.69 &
orientation = 0.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.PART_3.MARKER_6 &
adams_id = 6 &
location = 0.0, 5.0E-002, 1.38 &
orientation = 315.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.PART_3.MARKER_8 &
adams_id = 8 &
location = 0.0, 5.0E-002, 0.0 &
orientation = 315.0d, 0.0d, 0.0d
!
marker create &
marker_name = .ramp.PART_3.MARKER_21 &
adams_id = 21 &
location = 0.0, 0.408, 0.0 &
orientation = 315.0d, 0.0d, 0.0d
!
part create rigid_body mass_properties &
part_name = .ramp.PART_3 &
mass = 998.18756436 &
center_of_mass_marker = .ramp.PART_3.CG &
ixx = 169.0733423805 &
iyy = 163.992318131 &
izz = 16.2409275836 &
ixy = 0.0 &
izx = 0.0 &
iyz = 0.0
!
! ****** Graphics for current part ******
!
geometry create shape block &
block_name = .ramp.PART_3.BOX_3 &
adams_id = 3 &
corner_marker = .ramp.PART_3.MARKER_3 &
diag_corner_coords = 0.259, 0.358, 1.38
!
part attributes &
part_name = .ramp.PART_3 &
color = MAGENTA &
name_visibility = off
!
!---------------------------------- Contacts ----------------------------------!
!
!
contact create &
contact_name = .ramp.CONTACT_1 &
adams_id = 1 &
i_geometry_name = .ramp.PART_3.BOX_3 &
j_geometry_name = .ramp.ground.BOX_1 &
stiffness = 1.0E+008 &
damping = 1.0E+004 &
exponent = 2.2 &
dmax = 1.0E-004
!
contact create &
contact_name = .ramp.CONTACT_2 &
adams_id = 2 &
i_geometry_name = .ramp.PART_3.BOX_3 &
j_geometry_name = .ramp.PART_2.BOX_2 &
stiffness = 1.0E+009 &
damping = 1.0E+004 &
exponent = 2.2 &
dmax = 1.0E-003
!
!----------------------------------- Joints -----------------------------------!
!
!
constraint create joint revolute &
joint_name = .ramp.JOINT_1 &
adams_id = 1 &
i_marker_name = .ramp.PART_3.MARKER_6 &
j_marker_name = .ramp.ground.MARKER_7
!
constraint attributes &
constraint_name = .ramp.JOINT_1 &
name_visibility = off
!
constraint create joint revolute &
joint_name = .ramp.JOINT_2 &
adams_id = 2 &
i_marker_name = .ramp.PART_3.MARKER_8 &
j_marker_name = .ramp.ground.MARKER_9
!
constraint attributes &
constraint_name = .ramp.JOINT_2 &
name_visibility = off
!
constraint create joint fixed &
joint_name = .ramp.JOINT_3 &
adams_id = 3 &
i_marker_name = .ramp.PART_2.MARKER_10 &
j_marker_name = .ramp.ground.MARKER_11
!
constraint attributes &
constraint_name = .ramp.JOINT_3 &
name_visibility = off
!
constraint create joint fixed &
joint_name = .ramp.JOINT_4 &
adams_id = 4 &
i_marker_name = .ramp.PART_2.MARKER_12 &
j_marker_name = .ramp.ground.MARKER_13
!
constraint attributes &
constraint_name = .ramp.JOINT_4 &
name_visibility = off
!
constraint create joint fixed &
joint_name = .ramp.JOINT_5 &
adams_id = 5 &
i_marker_name = .ramp.PART_2.MARKER_14 &
j_marker_name = .ramp.ground.MARKER_15
!
constraint attributes &
constraint_name = .ramp.JOINT_5 &
name_visibility = off
!
constraint create joint fixed &
joint_name = .ramp.JOINT_6 &
adams_id = 6 &
i_marker_name = .ramp.PART_2.MARKER_16 &
j_marker_name = .ramp.ground.MARKER_17
!
constraint attributes &
constraint_name = .ramp.JOINT_6 &
name_visibility = off
!
!----------------------------------- Forces -----------------------------------!
!
!
!----------------------------- Simulation Scripts -----------------------------!
!
!
simulation script create &
sim_script_name = .ramp.Last_Sim &
commands = &
"simulation single_run transient type=auto_select initial_static=no end_time=0.7 number_of_steps=200 model_name=.ramp"
!
!------------------------------ Dynamic Graphics ------------------------------!
!
!
defaults coordinate_system &
default_coordinate_system = .ramp.ground
!
geometry create shape gcontact &
contact_force_name = .ramp.GCONTACT_6 &
adams_id = 6 &
contact_element_name = .ramp.CONTACT_1 &
force_display = components
!
geometry attributes &
geometry_name = .ramp.GCONTACT_6 &
color = RED
!
geometry create shape gcontact &
contact_force_name = .ramp.GCONTACT_9 &
adams_id = 9 &
contact_element_name = .ramp.CONTACT_2 &
force_display = components
!
geometry attributes &
geometry_name = .ramp.GCONTACT_9 &
color = RED
!
!---------------------------------- Accgrav -----------------------------------!
!
!
force create body gravitational &
gravity_field_name = GRAVITY &
x_component_gravity = 0.0 &
y_component_gravity = -9.80665 &
z_component_gravity = 0.0
!
!----------------------------- Analysis settings ------------------------------!
!
!
!---------------------------------- Measures ----------------------------------!
!
!
measure create object &
measure_name = .ramp.FY_contact &
from_first = yes &
object = .ramp.CONTACT_2 &
characteristic = element_force &
component = y_component
!
data_element attributes &
data_element_name = .ramp.FY_contact &
color = WHITE
!
measure create object &
measure_name = .ramp.FY_surf &
from_first = no &
object = .ramp.CONTACT_2 &
characteristic = element_force &
component = y_component &
create_measure_display = no
!
data_element attributes &
data_element_name = .ramp.FY_surf &
color = WHITE
!
measure create point &
measure_name = .ramp.FY_Upper_edge_1 &
point = .ramp.PART_3.MARKER_4 &
characteristic = total_force_on_point &
component = y_component &
create_measure_display = no
!
data_element attributes &
data_element_name = .ramp.FY_Upper_edge_1 &
active = off &
color = WHITE
!
measure create point &
measure_name = .ramp.Fy_Upper_edge_2 &
point = .ramp.PART_3.MARKER_4 &
characteristic = total_force_on_point &
component = y_component &
create_measure_display = no
!
data_element attributes &
data_element_name = .ramp.Fy_Upper_edge_2 &
active = off &
color = WHITE
!
measure create point &
measure_name = .ramp.MARKER_4_MEA_1 &
point = .ramp.PART_3.MARKER_4 &
characteristic = total_force_on_point &
component = x_component &
create_measure_display = no
!
data_element attributes &
data_element_name = .ramp.MARKER_4_MEA_1 &
active = off &
color = WHITE
!
measure create point &
measure_name = .ramp.MARKER_4_MEA_2 &
point = .ramp.PART_3.MARKER_4 &
characteristic = total_force_on_point &
component = y_component &
create_measure_display = no
!
data_element attributes &
data_element_name = .ramp.MARKER_4_MEA_2 &
active = off &
color = WHITE
!
measure create point &
measure_name = .ramp.MARKER_4_MEA_3 &
point = .ramp.PART_3.MARKER_4 &
characteristic = total_force_on_point &
component = mag_component &
create_measure_display = no
!
data_element attributes &
data_element_name = .ramp.MARKER_4_MEA_3 &
active = off &
color = WHITE
!
measure create point &
measure_name = .ramp.MARKER_8_MEA_1 &
point = .ramp.PART_3.MARKER_8 &
characteristic = angular_acceleration &
component = mag_component &
create_measure_display = no
!
data_element attributes &
data_element_name = .ramp.MARKER_8_MEA_1 &
color = WHITE
!
measure create point &
measure_name = .ramp.MARKER_8_MEA_2 &
point = .ramp.PART_3.MARKER_8 &
characteristic = total_force_on_point &
component = mag_component &
create_measure_display = no
!
data_element attributes &
data_element_name = .ramp.MARKER_8_MEA_2 &
color = WHITE
!
measure create point &
measure_name = .ramp.MARKER_4_MEA_4 &
point = .ramp.PART_3.MARKER_4 &
characteristic = total_force_on_point &
component = mag_component &
create_measure_display = no
!
data_element attributes &
data_element_name = .ramp.MARKER_4_MEA_4 &
active = off &
color = WHITE
!
measure create point &
measure_name = .ramp.MARKER_4_MEA_5 &
point = .ramp.PART_3.MARKER_4 &
characteristic = translational_displacement &
component = x_component &
create_measure_display = no
!
data_element attributes &
data_element_name = .ramp.MARKER_4_MEA_5 &
color = WHITE
!
measure create point &
measure_name = .ramp.MARKER_20_MEA_1 &
point = .ramp.PART_2.MARKER_20 &
characteristic = total_force_on_point &
component = mag_component &
create_measure_display = no
!
data_element attributes &
data_element_name = .ramp.MARKER_20_MEA_1 &
active = off &
color = WHITE
!
measure create point &
measure_name = .ramp.Force_On_point_Top_left_corner &
point = .ramp.PART_3.MARKER_21 &
characteristic = total_force_on_point &
component = y_component
!
data_element attributes &
data_element_name = .ramp.Force_On_point_Top_left_corner &
active = off &
color = WHITE
!
!---------------------------- Function definitions ----------------------------!
!
!
!--------------------------- Expression definitions ---------------------------!
!
!
defaults coordinate_system &
default_coordinate_system = ground
!
geometry modify shape block &
block_name = .ramp.ground.BOX_1 &
diag_corner_coords = &
(25.9cm), &
(5cm), &
(138cm)
!
geometry modify shape block &
block_name = .ramp.PART_2.BOX_2 &
diag_corner_coords = &
(40cm), &
(5cm), &
(138cm)
!
geometry modify shape block &
block_name = .ramp.PART_3.BOX_3 &
diag_corner_coords = &
(25.9cm), &
(35.8cm), &
(138cm)
!
material modify &
material_name = .ramp.steel &
youngs_modulus = (2.07E+011(Newton/meter**2)) &
density = (7801.0(kg/meter**3))
!
model display &
model_name = ramp