GRABCAD CHALLENGEGE Quick Connect 2015 Proposal

By: Reinaldo Wiener Rocca

PROJECT DESCRIPTION

The project consist of the design of a clamping mechanism for the brick-cavity design at the left and selection of a sealing material that prevents leaking during pressurization of cavity.

From grabcad.com

TECHNICAL REQUIREMENTS

No modifications allowed to the parts supplied

Materials must be compatible to work with water and between a temperature range of 1-40 °C

Sealing material to be defined in the proposal, must hold -1 to +3 bar pressure

Quick Connect Elements must be used Able to produce in mass Design simplicity Reliability of seal

STRATEGY

First a material for the seal was selected taking in account the technical requirements

Define the minimum pressure needed to avoid leakage.

Product scope: Reliable (35%): maintain the minimum pressure

to avoid leakage and resist dynamic loads Quick release and simplicity (30%) Low cost (20%) Maintenance (15%)

SEAL SELECTION

It was found in literature that a rubber is commonly used in water sealing, because of the low price and deformation properties. Furthermore EPDM is material that gives very good price-reliability balance

Extracted form Sealing Design Guide from Rogers Corporation

MINIMUM PRESSURE

Literature suggest a 50% of strain compression for a reliable seal and Stress-Strain curve gives the necessary pressure to maintain (≈ 6 MPa). In this case it is needed extra tools to assemble.

One-Dimensional Dynamic Compressive Behavior of EPDM Rubber, B.Song and W. Chen

FINAL PROPOSAL

MAIN ASPECTS

Reliability: High strength material was selected since high

forces were needed to maintain the pressure of the seal.

Sharp angles minimized to avoid fatigue failure, due to cyclic loads.

Simulations were performed to check all load scenarios.

Quick release and Simplicity The final product is very easy to assemble and

there is no need to use complicated tools. It is not necessary to use other tools rather than

a wrench to adjust the seal pressure.

MAIN ASPECTS

Low Cost: Reduced number of pieces, which are easy to

manufacture using machining or stamping processes.

An AISI 1020 can be used, which is a cheap material.

No esthetic design to minimize the manufacturing process.

Maintenance A paint or coating must be applied to the metal

surface to avoid corrosion or oxidation of the surface. This paint must the applied with frequency depending of the water exposure.