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@MASTERSTHESIS{Sambamurthy:1044179,
author = {Sambamurthy, Sivaraj Aditya},
title = {{D}esign and {FEA} {S}imulation of {I}nterference {F}it and
{A}utofrettage {P}rocess to {I}nduce {R}esidual {S}tresses
in a {H}igh-{P}ressure {C}ell},
school = {RWTH Aachen University},
type = {Masterarbeit},
address = {Jülich},
publisher = {Forschungszentrum Jülich},
reportid = {FZJ-2025-03068},
pages = {82 p.},
year = {2025},
note = {Masterarbeit, RWTH Aachen University, 2025},
abstract = {High-pressure clamp cells for neutron diffraction
experiments require specialized construction materials that
do not attenuate neutrons, are not activated, are
non-magnetic and can withstand high pressures. Previous
research found two commercially available materials,
Nickel-Chromium-Aluminium Alloy (NiCrAl) and
Copper-Beryllium Alloy (CuBe2), for a compound cylinder
clamped-cell designed for a maximum working pressure of 2.3
GPa. This pressure exceeds the yield strength of both
materials and previously employed strengthening mechanisms
to combat this issue were found unsuccessful. This work aims
to enhance the mechanical strength of the NiCrAl inner
cylinder to ensure safe usage of the clamped cell at high
pressures of up to 2.3 GPa through autofrettage. The study
also investigates the optimization of the interference fit
between the inner NiCrAl cylinder and the outer CuBe2
cylinder, aiming to further reinforce the structural
integrity of the cell. Through theoretical study and
numerical analysis using ANSYS Mechanical [ANSYS], a swage
autofrettage process is designed. A composite tungsten
carbide mandrel with 0.04 mm interference to the inner
surface of the cylinder is used to achieve a $20\%$ peak
overstrain, resulting in an increase of up to 872.7 MPa of
compressive residual stresses in the hoop direction at the
inner surface. The interference fit of the cylinders, using
H7/r6 tolerance class, generates a contact pressure between
22.07 MPa to 186.3 MPa at the contact surface. After
autofrettage and interference fit assembly, the compound
cylinder cell withstands internal pressure of 2.3 GPa with a
minimum safety factor of 1.18, indicating safe operation
under these conditions. Based on the findings, it is
suggested to perform autofrettage first on a straight
cylinder, followed by machining its outer surface to a
tapered profile for the subsequent tapered interference fit
with the outer cylinder.},
cin = {JCNS-2 / JARA-FIT},
cid = {I:(DE-Juel1)JCNS-2-20110106 / $I:(DE-82)080009_20140620$},
pnm = {632 - Materials – Quantum, Complex and Functional
Materials (POF4-632) / 6G4 - Jülich Centre for Neutron
Research (JCNS) (FZJ) (POF4-6G4)},
pid = {G:(DE-HGF)POF4-632 / G:(DE-HGF)POF4-6G4},
typ = {PUB:(DE-HGF)19},
url = {https://juser.fz-juelich.de/record/1044179},
}