July
11, 2002
Dear
Dick:
I
believe that we are going in the correct direction. SLAC must be able
to analyze
and predict the failure(s) before fixing the design. All uncertainties in the analysis must be understood and
accounted for, including flexure modeling, fastener fit-up, material property variability,
load
uncertainty, etc. I would like a list generated of these uncertainties
and a
mitigation strategy to address them. In
addition, I would like more assurance that the basic finite-element model is
correct. Previously, I requested model
checks for 1-g loading (constraint forces total applied weight), free-free
modes (rigid-body mode verification), and grounding.
Min Pham
was asking about recovery of dynamic forces, applied vs. developed.
This
should be included, too, in order to have confidence with the FEM.
I propose
that SLAC puts together a chart addressing verification of the
FEM. Previously, I asked for material properties
of the carbon-carbon. Theinformation
provided is too sketchy for me to make a proper assessment.
Therefore,
I am requesting the following carbon-carbon information:
Manufacturer
Fibers
Fiber Architecture
Densification Method
% Theoretical Density
Purchasing
Requirements (acceptance properties, workmanship requirements, inspection,
certification testing, etc.)
Design Allowables and Method of
Determination
Similar use of this material
In addition, I am requesting the following
information re the side panel composite:
Prepreg manufacture
Fiber
Weave Description
Resin
Resin Content
Purchasing Requirements
Cure Process
Fiber Volume
Void Volume
Laminate stacking sequence
Inspection (NDE)
Design Allowables
Similar use of this material
I am also concerned about the materials
and processes used to produce the sidewall insert attachments. For the aluminum insert, I want to know the following:
Bond Preparation Data (Processes,
Materials, Use of a Primer)
Bonding Process (Fixturing, Bond line
Control Method, Cure
Conditions)
Related
to these, I want to know about the process used to make the holes in the
carbon-carbon, hole inspection method and results, hole tolerance with the
insert (relates to insert bond line).
Lastly, I would appreciate more details on
the inspection done on all the parts, composites, and subassemblies.
Regards,
Ben
Rodini