Determination of the orthotropic material properties of individual layers of printed circuit boards

Fuchs, Peter; Pinter, Gerald; Tonjec, Maximilian

doi:10.1016/j.microrel.2012.04.019

Cited by 27 publications

(11 citation statements)

References 11 publications

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“…The Young's modulus and the yield strength of the copper foil were measured as E Cu = 50 GPa and R p0.2 = 178 MPa. The relatively low Young's modulus of electrodeposited copper foil corresponds to measured values reported in different literature sources [37][38][39]. The Poisson ratio of copper is taken from literature (ν Cu = 0.34) [40].…”

Section: Coppermentioning

confidence: 77%

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Adhesion energy of printed circuit board materials using four-point-bending validated with finite element simulations

Schöngrundner

Cordill

Maier

et al. 2015

Microelectronics Reliability

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Section: Coppermentioning

confidence: 77%

“…The Poisson's ratio ν 12 was calculated by averaging the negative ratio of transverse strain to longitudinal strain over the time. In order to determine the out-of-plane stiffness a mean field homogenization was used [37]. The resulting elastic properties for Pre-preg 1 and 2 are shown in Table 1.…”

Section: Pre-pregmentioning

confidence: 99%

Adhesion energy of printed circuit board materials using four-point-bending validated with finite element simulations

Schöngrundner

Cordill

Maier

et al. 2015

Microelectronics Reliability

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“…DIC is an optical measurement system used to track surface strains on a given test specimen. 9 The displacement controlled tests were performed on a Zwick Z250 (Zwick GmbH and Co. KG, Ulm, Germany) testing machine with a test speed of 10 mm/min until break. Longitudinal and transverse surface strains were identified from the ARAMIS system.…”

Section: Mechanical Characterisationmentioning

confidence: 99%

Analysis of the critical stresses in high-voltage composite winding insulations under thermal loads

Pothukuchi

Fuchs

Schuecker

2019

Journal of Composite Materials

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Stator bars are the critical components in generators with respect to their lifespan. The winding insulation may be susceptible to damage under excessive alternating temperature loads incurred by a high number of start–stop cycles and heavy overloads. The differences in thermal expansion between the different components in the multi-layered winding insulation lead to thermal stresses. This work deals with the thermo-mechanical characterisation of the individual constituents of the winding insulation and the finite element model of a stator bar, based on the material data obtained from the tests that enable the identification of the thermal stresses leading to delamination over thermal cycles. The out-of-plane and the interfacial shear stress are found to be in the critical range with respect to the relatively low cohesive strength of the included individual mica layers.

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“…They were calculated by micromechanic simulations. The measurements and the complementary simulations are described in detail in Fellner et al, 24 Fuchs et al 30 and Fellner. 31 The elastic properties of the copper foil were measured using a micro-dynamic mechanical analyzer.…”

Section: Experimental Characterizationmentioning

confidence: 99%

Cyclic mechanical behavior of thin layers of copper: A theoretical and numerical study

Fellner

Antretter

Fuchs

et al. 2015

The Journal of Strain Analysis for Engineering Design

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In printed circuit boards, thin copper layers are used as current paths. During the thermal loading of printed circuit boards, stresses arise due to the different coefficients of thermal expansion of the used materials. To be able to model the mechanical behavior of printed circuit boards under cyclic thermal loads, cyclic mechanical tests of thin copper foils under changing tensile and compression loads at different temperatures were conducted. From these experiments, the isotropic and kinematic hardening parameters were determined serving as material input data for a nonlinear isotropic/ kinematic hardening model in the finite element analysis-software Abaqus. The kinematic hardening parameters were fitted in an optimization process. The isotropic hardening variables were determined based on the stress versus plastic strain relationship that was constructed incrementally from the available individual cycles. The so-obtained curve was found to be not unique, but to depend on the loading situation. Hence, different approaches for strain range memorization were evaluated. Since these approaches were developed for modeling strain-controlled tests, whereas the experimental data were obtained in a force-controlled way, a phenomenological formulation was developed and applied. The results of curvature measurements during thermal cycling were used for model validation. The experimental results and the numerical predictions are in good agreement.

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Determination of the orthotropic material properties of individual layers of printed circuit boards

Cited by 27 publications

References 11 publications

Adhesion energy of printed circuit board materials using four-point-bending validated with finite element simulations

Adhesion energy of printed circuit board materials using four-point-bending validated with finite element simulations

Analysis of the critical stresses in high-voltage composite winding insulations under thermal loads

Cyclic mechanical behavior of thin layers of copper: A theoretical and numerical study

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