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Finite Element Model to Simulate PV Encapsulant Delamination

DuraMAT strives to develop a finite element model (FEM)—or cohesive zone model—capable of predicting and simulating the photovoltaic (PV) module failure mode of encapsulant delamination.

Within a PV module, there exists a complex and varying loading condition at the encapsulant interface, which serves as the driving force for delamination.  Fracture mechanics defines these loading conditions as one of three modes:

  • Mode I – opening
  • Mode II - in-plane shear
  • Mode III - out of plane shear.

Often in complex systems—such as a PV module laminate—a combination of these modes, or a mixed-mode loading condition, exists. While a recent effort has focused on developing the metrology to and assessing the Mode I critical strain energy release rate (GIc, adhesion) of the PV module encapsulant interface, knowledge of the Mode II and III behavior and the mixed-mode driving force at the PV module encapsulant interface is absent.

Therefore, we have embarked on a simultaneous course of experimental and modeling research to characterize the mixed-mode fracture behavior of the encapsulant/ PV cell interface and develop a fracture mechanics-based computational model. The model will incorporate the behavior, while modeling the driving force naturally developed in a PV module to predict and simulate delamination at this interface.

Primary Capability Areas

Predictive Simulation

Materials Characterization and Forensics

Location

National Renewable Energy Laboratory (NREL)

Applications

You can use the developed FEM to predict the mixed-mode delamination in PV encapsulant under thermal or mechanical loading. The critical material, geometry, and environment parameters generated from the FEM can provide guidance for PV module design.

Availability

This capability is available to NREL scientists and external collaborators.

References

Bosco, N.; Tracy, J.; Dauskardt, R; Kurtz, S. (2016). “Development and first results of the width-tapered beam method for adhesion testing of photovoltaic material systems.” Photovoltaic Specialists Conference (PVSC), 2016 IEEE 43rd (pp. 0106-0110). IEEE.

Davidson, B. D. (2015). “Standardization of the end-notched flexure test for Mode II interlaminar fracture toughness determination of unidirectional laminated composites.” Journal of Testing and Evaluation,43(6), 1540-1553.

Song, K.; Dávila, C. G.; Rose, C. A. (2008). “Guidelines and parameter selection for the simulation of progressive delamination.” ABAQUS User's Conference (Vol. 41, pp. 43-44).

Contact

To learn more about our FEM or cohesive zone model capability, contact Nick Bosco.