Leaves

The longest leaf in the spring which has the spring eyes is the master leaf. The other leaves are graduated leaves. The Leaves component has details of those attributes that you can vary and can enter them in tables or in .csv files. With every update that is made, the Help section changes accordingly.

Adding Master Leaf: The information that has to be entered in the Shape Input and Details tabs is explained in the following sections.

Shape

The shape of a leaf can be defined by either entering the data manually in the table or by importing a pre-defined .csv file. Once you import a pre-defined .csv file, the data is updated in the table and the corresponding graphics are displayed in the Canvas section.

X: Represents the x coordinate of leaf profile
Z: Represents the z coordinate of leaf profile.
Width: Defines the leaf width.
Tip: For constant width, only the first row needs to have the appropriate value, the rest of the rows must be zeroes.
Thickness: Defines the leaf thickness.
Tip: For constant thickness, only the first row needs to have the appropriate value, the rest of the rows must be zeroes.
Radius: Defines the side fillet radius.
Tip: For constant radius, only the first row needs to have the appropriate value, the rest of the rows must be zeroes.
Constant Width: Select to have the same values appear along the entire length of the leaf.
Constant Thickness: Select to have the same values appear along the entire length of the leaf.
Constant Radius: Select to have the same values appear along the entire length of the leaf.
Save Leaf Shape: Saves the entered leaf data in a .csv file format.

Refer to Shape Input for Leaf Property File section (below) for more information on how it is represented in the TiemOrbit file format.

Details

The options used in the Details tab are explained below.

Position in Stack

Defines the position of the leaf in a leaf stack, in simple terms the serial number.

Type

Defines the type of a leaf.

Master: The top leaf in the spring which has the spring eyes.
Graduated: Remaining leaves are called as Graduated leaves, with varying lengths.
Rebound: Any leaf that appears above the master leaf and is part of the pack.
Auxiliary: These are usually the helper leaf modeled at the bottom of the pack, to provide additional stiffness, whenever system is at a certain jounce.

Material

Defines the material used in a leaf.

Front Leaf Length

This is a read-only field and its values are auto-calculated. It provides length for the front half of the leaf from the center bolt.

Rear Leaf Length

This is a read-only field and its values are auto-calculated. It provides length for the rear half of the leaf from the center bolt.

For leaves with eyes, the length (Front/Rear) will be up to the point where the leaf starts curving into the eye profile. In other words, it indicates that length of the leaf which needs to be discretized using beam elements.

No. of Beams in front

Represents the number of beam elements that will make up the front half of the leaf.

No. of Beams in rear

Represents the number of beam elements that will make up the rear half of the leaf.

Shear Area Ratio Y

Defines the shear ratio along Y direction.

Specifies the shear area ratio in the y direction for Timoshenko beams. This quantity accounts for shear deflection in the Y direction. This is defined as:

Q_y is the first moment of the cross-sectional area to be sheared by a force in the y direction. l_z is the cross section dimension in the z direction. I_yy is the area moment of inertia about the beam y-axis. To neglect shear deformation in the y-direction, set ASY=0. ASY ≥ 0

Shear Area Ratio Z

Defines the shear ratio along Z direction.

Specifies the shear area ratio in the z direction for Timoshenko beams. This quantity accounts for shear deflection in the Z direction. This is defined as:

Q_z is the first moment of the cross-sectional area to be sheared by a force in the z direction. l_y is the cross section dimension in the y direction. I_zz is the area moment of inertia about the beam z-axis. To neglect shear deformation in the z-direction, set ASZ=0. ASZ ≥ 0

Angle with x-axis

Angle of the leaf with x-axis that is positive in the counter-clockwise direction and negative in the clockwise direction.

Figure 5. Detailed Leaf Spring for Leaf Details

Refer to the Leaf List for Leaf Property file section for more information on how it is represented in the TiemOrbit file format.

Bolt Location

Bolt Location is required only if the shape condition is Pre-Assembly. It provides the bolt location of a leaf as its reference location and generates correct leaf profiles from Pre-Assembly shape condition.

Refer to the Bolt Location for Leaf Property file section for more information on how it is represented in the TiemOrbit file format.

Adding Additional Leaves to the Leaf Stack (Graduated and Auxiliary Leaves)

Additional leaves can be added to the Leaves component and you must define the necessary points in the contact table to have contact between the upper leaves.

The information to be entered in the Contacts and Tip Contacts tabs is explained below.

Note: Please refer to the sections above for information regarding the Shape and Details tabs.

Contact Points

Contact points provide contact between the current leaf and upper leaf. In this section, define the number of contact points and enter the required data in the table.

The first leaf does not have contact points because it has no leaf to push against, above it.

Contact Number: Defines the serial number of contact points which should be unique for the front and rear direction.
Direction: Defines the direction of contact from the center bolt.
Distance from Center: Defines the distance of contact from the center bolt along the leaf length in either front/rear direction. While mentioning this, you will have to note the lengths of the current leaf and the leaf above it.
Contact Type: Defines the label of the contact properties that you have define in the contact properties component.

Refer to the Contact Table for Leaf Property File (*lpf) section for more information on how it is represented in the TiemOrbit file format.

Tip Contacts

Tip Liners

Tip liners are usually present in the leaf ends. Tip liners influence how the spring works. They are used to reduce the interleaf friction. Depending your needs, tip liners may have to be invoked. Tip liners can be at both ends or at one, as per your requirement.

The options used for Circular type are explained below:

Type: Defines the shape of the tip liner.
Radius: Defines the radius of the tip liner.
Thickness: Defines the thickness of the tip liner.
Contact Properties: Defines the label of the contact properties that you have defined in the contact properties component.

Figure 9. Leaf Data - Tip Contacts Tab with Tip Liner Option 'Off'

Figure 10. Leaf Data - Tip Contacts Tab with Tip Liner Option 'On'

The options used for Rectangular type are explained below:

Type: Defines the shape of the tip liner.
Thickness: Defines the thickness of the tip liner.
Width: Defines the width of the tip liner.
Depth: Defines the depth along the leaf.
Contact Properties: Defines the label of the contact properties that you have defined in the contact properties component.

Figure 11. Tip Liner Fields in Leaf Details

Refer to the Tipliner Front/Tipliner Rear for Leaf Property File (*lpf) section for more information on how it is represented in the TiemOrbit file format.

Leaves Block for Leaf Property File (*lpf)

Leaf List for Leaf Property File (*lpf)

In the Leaf List block of Leaf Property file, the Leaves Table sub-block attribute, type, and valid value to be entered in TiemOrbit file format are detailed in the following table. This table also provides information about the mandatory requirements for attributes. An example of how a Leaf List block is represented in a TiemOrbit file format is shown below:

Note: The number of leaves mentioned in the General Input block should match the number of leaves you enter in the Leaves Table. The Leaves Table sub-block can have any number of leaves but the Leaf Spring Builder will generate only those leaves that are mentioned in the General Input block.

For example, if the No. of leaves = 2, but a leaf list table has 3 leaves in its table, the Leaf Spring Builder will evaluate only the first two leaves of the table.

$------------------------------------------------------------------LEAF_LIST
[LEAF_LIST]
(LEAVES_TABLE)
{LEAFNO	LABEL	     TYPE		FRONTLENGTH		REARLENGTH    
NOOFBEAMSFRONT		   NOOFBEAMSREAR		MATERIAL}
1      LEAF1      MASTER      596.325      604.14     15      15      STEEL    
2      LEAF2      GRADUATED   548.0        560.0      15      15      STEEL    
3      LEAF3      GRADUATED   457.0        463.0      15      15      STEEL    
4      LEAF4      AUXILIARY   337.0        343.0      15      15      STEEL

Block Name = ‘LEAF_LIST’ (Required)

Sub-block Name = ‘LEAVES_TABLE’ (Required)


Attributes	Type	Valid Value	Required
Leafno	Integer	1, 2, 3 …	Yes
Label	String	Any unique label for each leaf.	Yes
leafType	String	Master Graduated Auxiliary Rebound	Yes
frontLength	Real	-	Yes
rearLength	Real	-	Yes
noOfBeamsFront	Integer	-	Yes
noOfBeamsRear	Integer	-	Yes
Material	String	-	Yes

Leaf Label for Leaf Property File (*lpf)

In the leaf label (Leaf1) block of Leaf Property file, the attribute, type, and valid value that has to be entered in TiemOrbit file format are detailed in the following table. This table also provides information about the mandatory requirements for attributes. An example of how a Leaf Label (Leaf1) block is represented in a TiemOrbit file format is shown below:

Note: This block is only required if the block name is mentioned in the “LEAVES_TABLE” sub-block of Leaf List block.

$-----------------------------LEAF1
[LEAF1]
LEAFPROFILEPATH = 'NONE'
LEAFROTANGLE = 0.0
MILITARYEYEFRNT = 'FALSE'
MILITARYEYEREAR = 'FALSE'
RADIUS = 'VARIABLE'
SHEARRATIOY = 0.0
SHEARRATIOZ = 0.0
SPACERWIDTH = 0.0
THICKNESS = 12.0
WIDTH = 101.2

Block Name = ‘LeafLabel’ (Required)


Attributes	Type	Valid Value	Description	Required
Width	Real String	‘VARIABLE’ Or width in mm	Defines the leaf width. Note: If leaf width is variable, use the Keyword = “Variable”. If the width is variable, the third column in the leaf profile data needs to specify the width.	Yes
Thickness	Real String	‘VARIABLE’ Or thickness in mm	Defines the leaf thickness. Note: If leaf thickness is variable, use the Keyword = “Variable”. If the width and thickness are both variable, the fourth column in the leaf profile data needs to specify the thicknesses. If only thickness is variable, third column in the leaf profile data needs to specify the thicknesses.	Yes
Radius	Real String	'VARIABLE' Or thickness in mm	Defines the side fillet radius.	Yes
leafRotAngle	Real		Angle of the leaf with x-axis that is +ve in counter-clockwise direction and vice-versa.	Yes
leafProfilePath	String	‘None’ Or File path	Defines the .csv file path at which leaf profile has been defined or you can pass “none” to define a leaf profile curve in the property file.	Yes
spacerWidth	Real	Default Value = 1.1mm	Defines the spacer gap between two leaves at the center bolt location. If not mentioned a default value of 1.1mm is used.	Yes
ShearRatio Z	Real	-	Defines the shear ratio along Z direction.	Optional
ShearRatio Y	Real	-	Defines the shear ratio along Y direction.	Optional
MilitaryEyeFrnt	String	'TRUE', 'YES', 'T', 'Y'	Defines military half wraps full wraps over the main spring eye. This must only be defined in Graduated leaf block.	Optional
MilitaryEyeRear	String	'TRUE', 'YES', 'T', 'Y'	Defines military half wraps full wraps over the main spring eye. This must only be defined in Graduated leaf block.	Optional

Each Leaf label block of Leaf Property file has the following sub-blocks.

Shape Input for Leaf Property File (*lpf)

An example of how a Leaf Shape sub-block is represented in a TiemOrbit file format is shown below:

(LEAFSHAPE)
{X		     Z		   WIDTH  THICKNESS   RADIUS}
  -596.3248901      164.9118722      64.0      7.0      0.0    
  -577.4098511      158.2104867      64.0     -7.0      0.0
  -559.5237427      148.6684792      64.0      7.0      0.0    
  -541.5889893      139.214988       64.0      7.0      0.0    
  -523.6109009      129.8471597      64.0      7.0      0.0    
  -505.6366882      120.4788278      64.0      7.0      0.0    
  -487.6898193      111.0495522      64.0      7.0      0.0    
  -469.7354431      101.6322701      64.0      7.0      0.0    
  -451.6985474      92.37851647      64.0      7.0      0.0

Block Name = ‘LeafLabel’ (Required)

Sub-block Name = ‘LEAFSHAPE’ (Optional)


Attributes	Type	Valid Value	Required
X	Real	-	Yes
Z	Real	-	Yes
Width	Real	-	Optional
Thickness	Real	-	Optional

Contact Table for Leaf Property File (*lpf)

An example of how a contact table sub-block is represented in a TiemOrbit file format is shown below.

(CONTACTS_TABLE)
{CONTACTNO   POSITION	DIRECTION	DISTANCE    CONTACT_PROPERTIES}
  2      INTERMEDIATE      FRONT	     95.0       METAL_METAL    
  3      INTERMEDIATE      FRONT	     155.0      METAL_METAL    
  4      INTERMEDIATE      FRONT	     234.0      METAL_METAL    
  5      INTERMEDIATE      FRONT            311.0      METAL_METAL    
  6      INTERMEDIATE      FRONT            385.0      METAL_METAL    
  7      INTERMEDIATE      FRONT            457.0      METAL_METAL    
  2      INTERMEDIATE      REAR      	105.0      METAL_METAL    
  3      INTERMEDIATE      REAR      	155.0      METAL_METAL    
  4      INTERMEDIATE      REAR      	234.0      METAL_METAL    
  5      INTERMEDIATE      REAR      	311.0      METAL_METAL    
  6      INTERMEDIATE      REAR      	385.0      METAL_METAL    
  7      INTERMEDIATE      REAR      	457.0      METAL_METAL

Block Name = ‘leafLabel’ (Required)

Sub-block name = ‘CONTACTS_TABLE’ (Optional)


Attributes	Type	Valid Value	Required
contactNo	Integer	1, 2, 3…	Yes
Position	String	‘TIP’, ‘INTERMEDIATE	Yes
Direction	String	‘FRONT’, ‘REAR’	Yes
Distance	Real	‘NA’ Or value	Yes
Contact Properties	String	Default = METAL_METAL	Yes

An alternate way of representing a contact table block in a TiemOrbit file is shown below. Rear and front strings defines the direction of contact from the center bolt.

(CONTACTS)
REAR = 5
FRONT = 5

Tipliner Front/Tipliner Rear for Leaf Property File (*lpf)

An example of how a Tipliner Front/Tipliner Rear sub-block for circular type is represented in a TiemOrbit file format is shown below:

(TIPLINER_FRONT)
SHAPE = CIRCULAR
RADIUS = 30
THICKNESS = 2.42
CONTACTPROPERTIES = METAL_PLASTIC

(TIPLINER_REAR)
SHAPE = CIRCULAR
RADIUS = 30
THICKNESS = 2.42
CONTACTPROPERTIES = METAL_PLASTIC

Block Name = ‘leafLabel’ (Required)

Sub-Block Name = ‘TIPLINER_FRONT’ or ’TIPLINER_REAR’ (Optional)


Attributes	Type	Valid Value	Required
Shape	String	'CIRCULAR'	Yes
Radius	Real	Less than the leaf width	Yes
Thickness	Real	-	Yes
contactProperties	String	No defaults	Yes

An example of how a Tipliner Front/Tipliner Rear sub-block for Rectangular type is represented in a TiemOrbit file format is shown below:

(TIPLINER_REAR)
SHAPE = RECTANGULAR
WIDTH = 64
DEPTH = 80
THICKNESS = 18.958
CONTACTPROPERTIES = METAL_PLASTIC

(TIPLINER_FRONT)
SHAPE = RECTANGULAR
WIDTH = 64
DEPTH = 80
THICKNESS = 18.958
CONTACTPROPERTIES = METAL_PLASTIC

Block Name = ‘leafLabel’ (Required)

Sub-Block Name = ‘TIPLINER_FRONT’ or ’TIPLINER_REAR’ (Optional)


Attributes	Type	Valid Value	Required
Shape	String	'RECTANGULAR'	Yes
Width	Real	Less than the leaf width	Yes
Thickness	Real	-	Yes
Depth	Real	-	Yes
contactProperties	String	No defaults	Yes

Bolt Location for Leaf Property File (*lpf)

An example of how a bolt location sub-block is represented in a TiemObit file format is shown below:

(BOLTLOCATION)
X = 0
Y = 0
Z = -154

Block Name = ‘leafShape’ (Required)

Sub-Block Name = ‘BOLTLOCATION’ (Optional)


Attributes	Type	Valid Value	Description	Required
X	Real	-	Specify the x coordinate of bolt location of leaf profile.	Yes
Y	Real	-	Specify the y coordinate of bolt location of leaf profile.	Yes
Z	Real	-	Specify the z coordinate of bolt location of leaf profile.	Yes