HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
<<  <  Page 4/4
Ann R. Thryft
User Rank
Blogger
Re: Its fair shair of problems
Ann R. Thryft   6/19/2012 2:27:28 PM
NO RATINGS
The main problem seems to be where composites interface with metals: and that is a new problem. It happens because a commercial plane is made of both materials: composites have not been designed to replace everything yet and metal can't be used everywhere due to weight/fuel reduction requirements. These problems took about 10 years to show up in in-service planes.

sensor pro
User Rank
Gold
Re: Its fair shair of problems
sensor pro   6/19/2012 1:25:25 PM
NO RATINGS
I would expect that these type of problems of material incompatibility would be first tested and then applied on smalled jet designs. The stress may be better detected at faster speeds and fuselage deformations under changing Gs.The chance of serious accident with many lives lost is a clear possibility. I would avoid this plane as a plague for now.

What concerns me the most a fast fixes.

Ann R. Thryft
User Rank
Blogger
Re: Its fair shair of problems
Ann R. Thryft   6/19/2012 12:32:16 PM
NO RATINGS
naperlou, I think the potential gap between existing modeling techniques and assumptions and the new realities of a new material is a good point, and one that the GAO was concerned about in its report addressing repairs to the Boeing 787's composites: http://www.designnews.com/document.asp?doc_id=235037 They focused on the back end of repair and maintenance, not the front end of design, but the concerns were similar.

Ann R. Thryft
User Rank
Blogger
Re: Its fair shair of problems
Ann R. Thryft   6/19/2012 12:31:00 PM
NO RATINGS
The fastener problem makes me, too, wonder about safety issues, regardless of what Airbus says. In a previous feature on fasteners, manufacturers told me they were designing new ones to go into new composite materials, which have very different requirements from metal. So what does that say about whatever fasteners or insertion techniques are currently being used? OTOH, composites in aircraft are not at all new and you'd think they'd have figured out that part by now.

naperlou
User Rank
Blogger
Re: Its fair shair of problems
naperlou   6/19/2012 9:22:09 AM
NO RATINGS
Beth, I agree with you.  I wouldn't fly one yet.  If they really could tell if it was safe they would not have had the problem.  This is new stuff.  They can't really know. 

I saw a similar situation on the Landsat spacecraft.  The structure was a large space frame made of composite tubes.  The joints were of metal (titanium, I think).  It was clear that if you put the fastrner holes in the normal position, as for an all metal structure, that there would be problems with cracks.  This was becuase of the use of dissimilar materials.  This was found by building a test sub-structure.  I wonder if Airbus did enough testing of actual materials, or whether they relied on CAE.  When using new materials it is important to understand that the CAE tools may not be able correctly predict what is happening. 

Jerry dycus
User Rank
Gold
Re: Its fair shair of problems
Jerry dycus   6/19/2012 8:24:16 AM
NO RATINGS
 

  I agree with Beth.   I wouldn't ride on one until fixed.

Facts are fasteners in composites if loaded are rarely that good unless very good design.  For lower labor, weight, higher strength they should have been glued together.

Bede glued his alum designs together from the 60's and many fighters, etc have too.  Not new tech at all.

Next why are they different materials?  It should have been one material or the other to keep  this from happening.

CF alsocan  cause corrosion in Alum, fasteners if not insulated well electrically.

Beth Stackpole
User Rank
Blogger
Its fair shair of problems
Beth Stackpole   6/19/2012 7:53:28 AM
NO RATINGS
Some how knowing there are cracks in the wings and knowing they aren't on track to be fully fixed until 2013 would make me very reticient to hop on one these babies, even though they are undoubtedly a beautiful example of A&D design.

Interesting that Airbus has suffered its fair share of setbacks on this plane, due mostly to miscommunications and missteps in the design process. To whit: One of the highly publicized delays related to the project was due to problems around the wiring harness system and the structural design--a miscue some attributed to interoperability and incompatibility issues between CAD platforms.

 

<<  <  Page 4/4


Partner Zone
Latest Analysis
A bold, gold, open-air coupe may not be the ticket to automotive nirvana for every consumer, but Lexus’ LF-C2 concept car certainly turned heads at the recent Los Angeles Auto Show. What’s more, it may provide a glimpse of the luxury automaker’s future.
Perhaps you didn't know that there are a variety of classes, both live and archived, offered via the Design News Continuing Education Center (CEC) sponsored by Digi-Key? The best part – they are free!
Engineer comic Don McMillan explains the fun engineers have with team-building exercises. Can you relate?
The complexity of diesel engines means optimizing their performance requires a large amount of experimentation. Computational fluid dynamics (CFD) is a very useful and intuitive tool in this, and cold flow analysis using CFD is an ideal approach to study the flow characteristics without going into the details of chemical reactions occurring during the combustion.
The damage to Sony from the cyber attack seems to have been heightened by failure to follow two basic security rules.
More:Blogs|News
Design News Webinar Series
12/11/2014 8:00 a.m. California / 11:00 a.m. New York
12/10/2014 8:00 a.m. California / 11:00 a.m. New York
11/19/2014 11:00 a.m. California / 2:00 p.m. New York
11/6/2014 11:00 a.m. California / 2:00 p.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Jan 12 - 16, Programmable Logic - How do they do that?
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  67


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service