Experimental-numerical approach to extract intrinsic interface
mechanical properties from a delamination experiment
Citation for published version (APA):
Murthy Kolluri, N. V. V. R., Hoefnagels, J. P. M., Dommelen, van, J. A. W., & Geers, M. G. D. (2010). Experimental-numerical approach to extract intrinsic interface mechanical properties from a delamination experiment. In S. Kyriakides (Ed.), Proceedings of the 16th US National Congress of Theoretical and Applied Mechanics, 27 June - 2 July 2010, State College, Pennsylvania, USA (pp. USNCTAM2010-859)
Document status and date: Published: 01/01/2010
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1 2010 USNCTAM 16th US National Congress of Theoretical and Applied Mechanics
June 27 - July 2, 2010, State College, Pennsylvania, USA
USNCTAM2010-859
EXPERIMENTAL-NUMERICAL APPROACH TO EXTRACT INTRINSIC INTERFACE
MECHANICAL PROPERTIES FROM A DELAMINATION EXPERIMENT
M. Kolluri*
Material Innovation Institute (M2i) Delft, The Netherlands & Eindhoven University of Technology
Eindhoven, The Netherlands
m.kolluri@tue.nl
J. P. M. Hoefnagels
Eindhoven University of Technology Eindhoven, The Netherlands
J. A. W. van Dommelen Eindhoven University of Technology
Eindhoven, The Netherlands
M. G. D. Geers
Eindhoven University of Technology Eindhoven, The Netherlands
ABSTRACT
Mechanical properties of interfaces between elasto-plastic and elastic materials are difficult to characterize because of the complex plastic dissipation during delamination experiment. These interfaces are typically relevant for System-In-Package (SIP) microsystems. Typical systems include lead frame – molding compound epoxy interface structures (LF – MCE) used in packaging industry, which are extensively studied because of their wide applications in semiconductor packaging industry and their frequent failures during manufacturing and processing.
Experiments on LF- MCE interface structures using our advanced miniature mixed mode delamination setup (Fig. 1), capable of in-situ characterization of interface delamination [1], have shown the presence of permanent deformation (Fig. 2) after complete unloading which originates from bulk and/or interface plasticity. Therefore, to extract intrinsic interface mechanical properties, an intelligent post treatment analysis of the data (e.g. force displacement response) from delamination experiment is needed.
In this work, consequences of this plastic dissipation
on load displacement response of the delamination
experiment and on the calculation of CERR are discussed,
and a procedure to extract intrinsic interface mechanical
properties from an in-situ delamination experiment is
presented. Finite element analysis is used with an
elasto-plastic material model and an advanced cohesive zone
interface model to simulate the experiment and to
understand the origin of the observed permanent deforma-
tion in the experiment. An improved Xu-Needleman’s
cohesive zone model developed in our group [2] was
MMMB micro-tensile stage SEM chamber (a) hinge (b) (c) sample MMMB micro-tensile stage SEM chamber (a) hinge (b) (c) sample
FIGURE 1. (a) MINIATURE MIXED MODE BENDING
(MMMB) SETUP MOUNTED IN (b) MICRO TENSILE STAGE AND EVENTUALLY IN (c) SEM CHAMBER FOR
2 2010 USNCTAM FIGURE 3. (a) NORMAL AND (b) TANGENTIAL
TRACTION SEPARATION CURVES OF AN IRREVERSIBLE COUPLED MIXED MODE COHESIVE
ZONE LAW TO MODEL PLASTICITY AT THE INTERFACE. (L: LOADING, UL: UNLOADING, RL:
RELOADING) (a)
(b)
chosen to model the interface because of its applicability
to mixed mode loading cases. The unloading behavior in
this cohesive zone law was extended with damage and
plasticity under coupled mixed mode load cases to
capture the interface plasticity (Fig. 3). From the
numerical delamination experiments, the additional
microscopic information that is needed to isolate interface
properties from bulk plastic dissipation was identified.
Based on this extensive numerical analysis a post
treatment procedure to extract the intrinsic interface
mechanical properties from the experimental data is
proposed.
REFERENCES
[1] Kolluri, M., Thissen, M.H.L., Hoefnagels, J.P.M., Dommelen, J.A.W. van, Geers, M.G.D. In-situ characterization of interface delamination by a new miniature mixed mode bending setup. Int. J. Frac., 158: 183-195, 2009.
[2] Bosch, M.J. van den, Schreurs, P.J.G., Geers, M.G.D. An improved description of the exponential Xu and Needleman cohesive zone law for mixed-mode decohesion. Engg. Frac. Mech., 73: 1220-1234, 2006.
(a)
FIGURE 2. LOAD-DISPLACEMENT RESPONSE FROM
A MODE-I EXPERIMENT. PERMANENT DEFORMATION IS OBSERVED AFTER COMPLETE UNLOADING.
Residual displacement Residual displacement
