padeye plus user manual -...

PADEYE PLUS – Padeye Design and Optimizer for Un-stiffened Padeyes

User Manual

Version : 1.0.0

Date : 07-November-2014

PADEYE PLUS User Manual

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License Information

PADEYE PLUS

PADEYE PLUS software and source code are property of Technomak Offshore & Marine

Consultancy. The software along with this user manual allows the purchaser to use the

software for commercial and non-commercial purpose.

DISCLAIMER OF WARRANTY

Neither Technomak Offshore & Marine Consultancy (and its group of companies), nor the

author of this program and documentation are liable or responsible to the purchaser or user for

loss or damage caused, or alleged to be caused, directly or indirectly by the software and its

attendant documentation, including (but not limited to) interruption on service, loss of business,

or anticipatory profits.


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Contents _

License Information ................................................................................................. 2

About PADEYE PLUS ............................................................................................... 4

Unit System .............................................................................................................. 5

PADEYE PLUS Inputs .............................................................................................. 5

Padeye Properties Calculation ................................................................................ 8

Modifying the Results .............................................................................................. 9

PADEYE PLUS Output ............................................................................................. 9

Limitations ................................................................................................................ 9

References .............................................................................................................. 11

Appendix ................................................................................................................. 12

Appendix 1.1 - Example 1 ..................................................................................... 13 Appendix 1.2 - Example 2 ..................................................................................... 21


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About PADEYE PLUS

PADEYE PLUS is designed for iOS platforms and available on iPhone and iPads. This manual

gives step by step procedure to use the software, which can be used to design, optimize and

modify unstiffened padeyes for offshore, onshore and harbor lifts. PADEYE PLUS

automatically calculates matching shackle, optimum plate grade and thickness, clearances

between shackle and padeye. The user can edit and modify the padeye parameters to suit their

specific requirements and available inventory. Padeye design is carried out in accordance with

AISC Allowable Stress Design (9th Edition), API-RP-2A Working Stress Design (21st Edition) and

best practice in the industry. You can download and install PADEYE PLUS from App Store.


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Unit System

Current version of PADEYE PLUS uses millimeter-Metric Tons. Angular measurements are in

degrees.

PADEYE PLUS Inputs

Main input sheets for PADEYE PLUS is similar to the below. The user interface may vary

depending on the platform and equipment (iPad or iPhone).

Input Sheet


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Padeye SWL

This is the padeye safe working load for which padeye is to be designed. If there are no specific

requirements, user may input only the static load. All factors of safety based on best industrial

practice and design codes are automatically included during design and optimization.

OOP Angle

This is the actual out of plane angle (angle between padeye plane and sling) for the padeye.

This may be left empty, in which case a default OOP angle of zero degrees will be considered

for Offshore/Harbour lift, zero for Onshore lift and 2.5 degrees if the padeye is designed for DNV

standards. To override default values, input actual OOP angle in degrees.

It is not a good practice to provide unstiffened padeyes for higher OOP angle. To prevent

accidental input error, a warning message is displayed when the OOP angle is greater than 10

deg for lift weight >= 100 MT or OOP angle is greater than 15 deg for a lift weight of < 100 T.

Factor of Safety

Factor of safety is the design factor including dynamic factor, consequence factor and skew load

factor. This may be left empty, in which case the software considers a factor of safety of 2.0 for

Offshore lifts, 1.5 for Harbour lifts and 1.35 for onshore lifts. User can override the default

values by entering the required Factor of Safety.

Sling Angle

Sling angle is the angle made by sling with horizontal. This may be left empty, in which case a

default sling angle of 60 degrees will be used for Offshore/Harbour lifts and 45 degrees for

Onshore lifts. However, if your padeye is symmetrical, the default sling angle is 90 degree.

User may enter the actual sling angle. The software automatically designs the padeye for the

sling angle ± 5 deg.


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Lift Type

Default lift type is Offshore, which can be changed to Harbour lift or Onshore lift based on the lift

condition. If the lift is land lift with moving crane, harbor lift shall be selected. Proper selection

of lift type will ensure that the recommended factor of safety is automatically selected.

Click on the button to get quick help on the inputs.

Icons and Symbols

Click the Email Icon on the ‘Basic Parameters’ and ‘Advanced Parameters’ tab to email the result.

To display this user manual, click . User can email the user manual by

clicking the Email Icon below the user manual.

Click at any stage to go back to the previous screen.

Use to display the About Box.


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Padeye Properties Calculation

When the user finishes the inputs and clicks button, the software tries to find

an optimum padeye based on the inputs. It uses the best industrial practice, recognized design

codes (AISC-ASD, API-RP-2A-WSD and DNV 2.7-1). It also selects an optimum shackle and

checks the key parameters such as jaw width clearance, clearance between inside of shackle to

the padeye (including reduced clearance for lifting slings) and all the unity ratios including

bending unity ratios. The result screen after optimization is similar to the below.

Optimization

‘Basic Parameters’ Tab ‘Advanced Parameters’ Tab


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Modifying the Results

User is allowed to edit and modify any of the key padeye parameters – from main dimensions of

padeye to material grade, shackle, thickness and number of main plates, cheek plates and

spacer plates. User can use this to suite the available shackle dimensions and material

inventory. Click on the button to edit the parameters. When the user changes the material

grade, reduction in yield strength according to thickness is automatically applied. Then the

padeye is changed, the pinhole diameter for main plates, cheek plates and spacer plates are

automatically resized to suit the selected padeye pin.

PADEYE PLUS does not overwrite the calculations when the changes are made. To make the

modifications effective in the output, user should press .

IMPORTANT

PADEYE PLUS Output

PADEYE PLUS output is displayed when calculation is complete and Report Icon is

selected. AISC and Combined stress checks are carried out for all designs. If DNV Stress

Check is checked, additional output is displayed with DNV contact stress and Tear-out stress.

The results can be emailed in pdf format, if your device supports email functionality, by clicking

Email Icon .

Limitations

1. Current version of PADEYE PLUS is specifically made for offshore industry and uses

Working Stress Design methodology only. We can implement design codes such as

LRFD etc. based on customer feedback.

2. In some cases, the optimizer may not converge. This is mainly because the optimizer

fails during geometry check (such as jaw width clearance). In such a case the App

throws a message as below.


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In such a situation, it is recommended to review the results by clicking the Report icon

and manually change the last optimized parameters.

3. While changing the shackle, user needs to first select the shackle before pressing the

Select Icon . This is a known issue and user is requested to select the desired

shackle first.

4. In some cases, the output may display ‘*FAIL*’ in the geometric compatibility check.

This is mostly because the iteration converged to an adequate padeye, but failed to

select a proper spacer plate. In such a case, user is requested to the

results by manually changing the spacer plate thickness.

5. The optimizer is suitable for padeyes between 1.0 MT and 1814MT. Due to the same

reason mentioned in (4), the geometric compatibility with available shackle size may fail

for very small padeyes, in which case the user is requested to design manually.

6. Present version does not include the spacer plate in the drawing produced. User shall

take care to include the spacer plate as per the recommendation.


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References

1 "Manual of Steel Construction – Allowable Stress Design”, 9th

2.

Edition, by American Institute of Steel Construction "Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms – Working Stress Design", API-RP-2A WSD, 21st

3.

Edition, by American Petroleum Institute “Standards for Certification – Offshore Containers”, June 2013, DNV 2.7-1 by Det Norske Veritas


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Appendix


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Appendix 1.1 - Example 1


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Objective :

The purpose of this exercise is to design a padeye of 55 MT capacity for Offshore use. The

padeye shall also conform to DNV 2.7-1 guidelines.

Inputs for the optimization is as below. Ensure that the ‘DNV Stress check’ is checked.

Input Screen

Upon pressing , output similar to the below is obtained.


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Output of Example-1


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Verification of the inputs indicates that the minimum out of plane angle of 2.5 deg (for DNV 2.7-

1) is automatically selected. Sling angle is default for offshore lift (60 deg) and factor of safety is

default for offshore lift (2.0 as per API-RP-2A WSD). Most suitable shackle and list of

compatible shackle with minor variation in pinhole diameter is also listed. Out of plane shear

force (9.81 * (55 * sin(2.5) + 0.05 * 55) = 50.512 KN) is calculated in accordance with the OOP

angle and considering API recommendation.

Geometrical compatibility is checked and spacer plate to suit the recommended shackle spread

is also automatically selected.

Padeye obtained has a maximum unity ratio of 0.9631, indicating the results are optimized. The

results can be manually verified.

A not-to-scale drawing of the padeye is also produced along with the report which can be used

for production.


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Appendix 1.2 - Example 2


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Objective: A generic padeye of 200 MT lifting capacity for offshore use with a factor of safety of 2.5 is to be

designed. The padeye shall also have a design out of plane angle of 1.0 deg. Available plate of

25mm S355J2G3 is in stock. Further the available shackle is 250MT Greenpin-6033. Padeye

designed shall suit the available shackle.

Step 1:- Get an optimum design for SWL of 200MT, Factor of Safety of 2.5 and OOP angle of

1.0 deg. Input screen is shown below.

Input Screen


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Pressing gives an optimum padeye as per below screen shot.


However, as you noticed, the shackle and plate sizes are different. You can change the shackle

by pressing the Crosby,200.0 T button, which gives a list of shackles in database. Scroll down

and select the 250 T Greenpin-6033 from the list and press . Screenshot for the steps is as

below.


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Select 250 MT Greenpin-6033 from list Press . An alert message

confirming the selection is displayed

The main plate thickness is to be changed from 60mm to 63.5mm and the outer cheek plate

thickness to be changed from 22.5mm to 25.0mm. To change the plate thickness, select the

‘Advanced Parameters’ Tab. You can click on the plate thickness 60.000 and 22.500 . A

user input message asking for the new thickness appear. Once the values are filled in, the table

is updated as per below.


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Click on the cheek plate 5&6 and

change to 25mm

The final screen after the thickness changes should appear as below.


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Which verifies that the changes have been accepted. Press to rerun the

new analysis and update the report. The report generated will be similar to the below. Review

the output and you can see that the plate thickness are changed and the Shackle is also

changed to selected shackle. Further the pinhole dia, and parameters related to shackle (jaw

width, inside length etc) are also changed.


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Output of Example-2


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