Welcome to Law-Forums.org!   

Advertisments:




Sponsor Links:

Discount Legal Forms
Discounted Legal Texts


Pressure Required To Break Ice

The law of the sea.

Pressure Required To Break Ice

Postby Chuminga » Mon Dec 12, 2016 1:45 pm

How much pressure does it take to fracture ice?  I am designing an ice cube cutter, and need to do some preliminary analysis.
Chuminga
 
Posts: 49
Joined: Sun Feb 02, 2014 2:53 pm

Pressure Required To Break Ice

Postby courtland87 » Mon Dec 12, 2016 3:24 pm

How much pressure does it take to fracture ice?  I am designing an ice cube cutter, and need to do some preliminary analysis.
courtland87
 
Posts: 46
Joined: Wed Dec 11, 2013 4:55 am

Pressure Required To Break Ice

Postby Noach » Tue Dec 13, 2016 11:25 pm

This is not strictly in my field, but as it happens I have a current interest in the strength of ice so I may be able to give some pointers.

First you should try to get hold of a copy of Engineering Materials Vol 2 by Ashby and Jones, this has a worked example of ice fracture as a case study and it is from this that I am giving this answer.  This book quotes the tensile strength of ice as 1MPa, compressive strength 6MPa and fracture toughness as 0.12MPam1/2.  However you should appreciate that these properties will vary from one piece of ice to another depending upon its microstructure.  This will depend itself upon how it was frozen, storage conditions and possibly water purity.

As ice is a brittle solid at the strain rates you are likely to be using, you could treat this as a brittle fracture problem.  Under the imposed load from the cutter the ice should fracture due to tensile stresses generated by the load(even though the input load is compressive).  The actual fracture mode and hence the load will be sensitive to the cutter geometry(thickness and tip angle) and the microstructure of the ice.

In practice it seems likely that the cutter would indent the cube then act as a wedge to fail the cube in tension by fast fracture.  Actually calculating the cutter load to fracture the ice gets a bit complex as you need to know quite a few details of contact geometry and make assumptions about ice cube flatness.  

You could start by calculating the required tensile load to pull the cube apart - probably around 600N for a 25mm cube.  But this is obviously much too high for a brittle material.   

Or using the compressive strength calculate the load to push a thin blade through the cube - about 150N for per mm of blade thickness, neglecting friction.

So a relatively low load(150N for 1mm wide flat face) will start to indent the cube and then fracture will probably occur.

I hope this at least gives you some ideas.  
Noach
 
Posts: 39
Joined: Tue Feb 04, 2014 4:26 pm


Return to Maritime Law

 


  • Related topics
    Replies
    Views
    Last post