Product and System Design

Automation of repeated design tasks.Summary

In this project I will present the stages in making an automation design for the Hatch for bulk carriers. To simplify the calculations we minimize the structure of the hatch. We will take in consideration just the next element: Side plate transversal Side plate board Side plate centre Primary transversal Longitudinal flange Top plate.First off all Ill show the structure calculations for the hatch, then the main drawing from which we start the automation in Solid Works, then operations done in Solid Administrator to make the needed structure.List of AbbreviationsThis are all abbreviations used in calculations and solid administrator:t- thickness from plate calculations,s- No. of stiffeners,x- No of spaces between stiffeners,p- Pressure on the top plate,B- Width of the hatch,L length of the hatch,g1 - thickness calculated with bending moment for C profile,g - thickness calculated with bending moment for I profile,Wy bending moment for I profile,Wy1 bending moment for C profile,h1 - height for side plate board (=height*0.75, where height is average height of the hatch),H- height for side plate center (=height*1.3, where height is average height of the hatch),Fdeflection- the force on the all surface of the hatch for the calculation with deflection,lwplf- longitudinal width for plate longitudinal flange,gdeflection1- thickness calculated with deflection formulas for C profile,gdeflection - thickness calculated with deflection formulas for I profile,f- Deflection for I profile,f1- Deflection for C profile,NA- neutral axis for I profile,NA1- neutral axis for C profile,- Maximum bending stress,M- inertia moment b - Bottom plate width for C profile,a - Bottom plate width for I profile,E- Elastic modulus for steel,spt- Side plate transversal,spb- Side plate board,spc- Side plate centre,pt- Primary transversal,plf- Longitudinal flange,tp- Top plate.We use t-thickness, w-width, l-length+ the which kind of plate for each dimension.

Introduction

A hatch is a complex structure used mainly for bulk carriers, but not only. We can use hatch in the offshore business for closing the moon pool on top and even on the bottom. There are many kinds of hatches but most important are: Lift-away hatch covers Rolling hatch covers Hydraulic folding hatch covers.The hatches have to have the next features: weather tightness durability optimized weight/strength ratio combined with sophisticated technical solutions.For our case we have:We are going to automate the design of a hatch cover. The design of the hatch cover has following input variables: Opening width Opening length The design pressure on the top of the hatch cover (typically 1-1,75 tons/m2).The design is constrained by following: Welded steel structure Maximum bending stress: of 160 N/mm2 Maximum deflection: 0,0028*Width

Calculations

Primary transversal, 3 types of calculations:No.1 Plate calculations

x- Number of stiffeners

B width,x roundup, e.g. x =8.1, this means x=9

p- Pressure on the top plate

No.2. Thickness calculated with bending moment for I profile:

No.3 Thickness calculated with deflection formulas for I profile