fem analysis_portfolio_krishnaprasad

FEM PORTFOLIO

KRISHNA PRASAD

STRUCTURAL ENGINEER

GL NOBLE DENTON

MAJOR FEM ANALYSES

TOPSIDE STRUCTURAL INTEGRITY ANALYSIS

SPUD CAN ANALYSIS

JACKCASE ANALYSIS (Pinion and hydraulic)

CRANE PEDESTAL ANALYSIS

TRUNION ANALYSIS

SCF CALCULATION BY FEM

HELIDECK ANALYSIS


Project : Independent Verification Report- Structural integrity for Topsides and lifting consoles

Client :Dry dock world Dubai

Finite element analysis and buckling calculation for Dolwin 2 semisubmersible Topside and the analysis of Lifting consoles

Dolwin-2 topsides is a steel framed model with 89.7m length, 71.5m width and 19.5m height. It has three horizontal levels of deck framing-main deck level, intermediate deck and weather deck.

Modelling and analysis is done in Abaqus 6.10-1


The 10,000 MT topsides of Dolwin-2 HVDC semisubmersibles are to be lifted

and mated on to the hull structure using ALEs gantry system at Dubai Dry

docks.

The lifting of the Dolwin-2 topside is carried out using a gantry system with

hydraulic strand lift units positioned on top of beams above each of the four main

support towers and two A-frame supports.

INTEGRATED TOPSIDE MODEL WITH CONSOLE

-THREE DIMENSIONAL VIEW

INTEGRATED TOPSIDE MODEL WITH

CONSOLE SECTIONAL VIEW ABOVE MAIN

DECK LEVEL

FWD/AFT CONSOLE

FWD/AFT CONSOLE (TOP COVER PLATES ARE

HIDDEN)

MIDDLE LIFTING CONSOLE

MIDDLE LIFTING CONSOLE (COVER PLATES ARE

HIDDEN)

Factored self weight and Wind load are considered for the analysis. The factors arebased on the DNV Rules for Marine operations.

Total load of the topside is increased by factoring the acceleration due to gravityaccording to the different load cases.

For the local analysis of the Lifting Consoles,The sling reactions from the integratedmodel applied at the anchor head of the lifting console as pressure load

For the structural integrity analysis of the topsides, the slings are modelled as axialmembers along with the integrated topside model

TOPSIDES-RESULT PLOTS

SPUD CAN ANALYSIS

Project :OCD035-Design GPC JU 125/300

Client :GPC

Objectives:FEM analysis of Spud can

Spud can is the foundation of individual leg in Jack up

Spud can diameter is 14m and height is 4.375m.Out of three One of the spud can is modelled

Loads are applied according to ABS MODU part 3

and analysed for maximum reaction (6000T) from in place condition

Modelling and analysis is done in Abaqus 6.10-1

SPUD CAN MODEL

FEM ANALYSIS RESULTS FOR BOTTOM

PLATE

FEM ANALYSIS RESULTS FOR TOP PLATE

JACKCASE ANALYSIS

Client :GPC

Objective:FEM analysis of Jack case

Jack case is a important structure for jack up rig.

The rising and lowering of leg and Rising and lowering of hull are done by jacking system

Jacking system of GPC JU 125/300 is of pinion-electrical motor type

Out of the three jack cases, one is modelled analysed for critical consistent load sets

Critical load sets are identified from Global inplace analysis, Ocean &Field tow analysis and Maximum preload holding capacity

Modelling analysis and drawing preparation is Critical

Worked along with ZPMC engineers for Integrated analysis

The pinion loading is redefined to include the local motor loading effects in the jacking frame.

JACKCASE ANALYSIS

CONTD

Model with mesh

JACK CASE GEOMETRIC MODEL

FEM RESULT FOR ONE EXTREME CASE


Project : OCD042 Sagar Samrat Conversion ProjectClient : ONGC

Objective: FEM analysis of Crane pedestal

Crane pedestal is the foundation structure for crane. Modelling

and analysis done three time as per the changes in SHI dwg.

At the same time this crane pedestal is supporting the beams from the

technological structure. The connection is moving connection

COMBINED STRESS PLOT FOR ALL CASES

JACKCASE ANALYSIS

Project : OCD042 Sagar Samrat Conversion Project

Objectives:FEM analysis of Jack case

Out of four jack cases, one is modelled and analysed for critical load sets

It is hydraulic pin type jacking system

JACKCASE ANALYSIS

JACKCASE ANALYSIS

Modelling and analysis are done similar to the previous jacking system analysis

Challenge: Working with Old drawings

Here the jacking frame is absent

The loads from the hydraulic system is applied to the upper shock foundation to simulate the real phenomenon

Lower and upper guide loads are applied as pressure. The loads are extracted from Final Inplace analysis for different conditions.

JACKCASE ANALYSIS RESULT PLOTS

TRUNION ANALYSIS

Project : OCD048-Top side installation

Objectives: FEM analysis of Trunnion

TRUNION ANALYSIS

Shell modelling

Maximum Lifting load is considered

(2750T).

In plane and out of plane loads are

considered for the analysis.

TRUNION ANALYSIS

TRUNION ANALYSIS

The edges of the deck beams are pinned and the load is applied as pressure load for initial

analysis, and modified to line load later.


Objectives: Crane pedestal analysis

Rated Capacity of Crane -55T

Pedestal is attached to the side shell

Pedestal is analysed for the maximum loads from the vendor: Modelling and analysis are done similar to crane previous pedestal analysis


Objectives: SCF calculation

A particular joint with chord and braces are modelled using shell elements

Axial load, inplane and out of plane bending loads are applied to calculate the SCF

Pinned boundary condition is used at a distance equal to two bays

SCF= Hot Spot stress/Nominal stress

SCF CALCULATION BY FEM-FINE MESHED

AREA NEAR THE JOINT

HELIDECK ANALYSIS

The helideck and its support structure is analysed in SESAM-Genie for various loading conditions and loading combinations.

Different loading conditions are considered as per CAP 437

HELIDECK ANALYSIS

HELICOPTER DETAILS

The Helideck is designed considering the helicopter types SIKORSKY S61N and SIKORSKY S92.

SIKORSKY S61N

Overall Length : 22.2 m

MTOM : 9.3 t

Landing Gear Separation : 4.27 m

SIKORSKY S92

Overall Length : 20.88 m

MTOM : 12.8 t

Landing Gear Separation : 3.18 t

RESULT PLOT

Thank you

fem analysis_portfolio_krishnaprasad

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