Lightning Strike Ablation

Significance of Research:

• According to statistics, each commercial airplane encounters 1 lightning strike per year on average.

• Lightning strike also poses serious concerns for UAVs.

• Lightning strike not only causes cosmetic damage (e.g., paint peeling), but also delamination, fiber breakage, burning, and charring of aerospace composite materials.

• Need to understand the material response under lightning strike conditions, so as to come up with better material designs to mitigate lightning strike hazards.

• Validated computational models can help aerospace engineers to easily screen novel designs of materials for improved lightning strike protection of aircraft.

Research Highlights:

• Lightning-strike-induced thermal response and ablation in laminated glass fiber reinforced polymer matrix composites were investigated.

• Lightning channel parameters such as non-uniform current density and heat flux were determined.

• Lightning arc channel expansion was considered.

• An element deletion method using FEA was proposed to solve the nonlinear heat transfer problem with moving boundary conditions.

• Temperature-dependent material properties of fiber reinforced polymer matrix composites were considered.

• U. of Florida has decided to exert software copyright for the Element Deletion codes, Jan. 4, 2018.

Modeling with Progressive Element Deletion Method (Set Temperature as Element Deletion Criteria)

Example 1: Modeling progressive ablation (material removal) process using our developed Element Deletion Method. In this simulation, the elements are removed once the temperature reach a certain prescribed limit.

Example 2: Modeling progressive ablation (material removal) process: Verification of the proposed Element Deletion Method by comparing with the traditional UMESHMOTION subroutine +ALE method. (see Wang & Zhupanska, 2018). Source code for Example 2 can be downloaded in this webpage. Kindly please cite the papers if you plan to use the code for your own project. Thank you very much for your interest!

Note: UMESHMOTION subroutine +ALE method is the traditional method in ABAQUS used to model ablation problems (see ABAQUS Documentation - Abaqus example problems guide - section 3.1 Tire Analysis). However, such a method is not applicable if the target material is inhomogeneous (e.g., laminated composites materials with different layer orientations) due to the limitation that mesh is not allowed to flow from one material domain to another (e.g., from one laminate layer to another). Therefore, this motivated us to develop the Element Deletion Method to enable ABAQUS with the capability of modeling ablation for laminated composite materials. This simple example is used to verify our developed Element Deletion Method by comparing the output with the output obtained from the traditional UMESHMOTION subroutine +ALE method.

Model data for Example 2:

Heat source: uniform heat flux on top of a 2D plane

Material: Isotropic

Ablation rate: prescribe to be a linear function of time (source codes can be modified to model with ablation rate as a function of surface temperature): s(dot) = 5000000*time (unit in microseconds) -50. Unit of s(dot) is in m/s.

Source code for Example 2 is uploaded and ready to be downloaded, in which it contains two files: Umeshmotion.zip and Element Deletion.zip. Instructions for running the code are included.

Note:

• Umeshmotion.zip contains the files for the traditional UMESHMOTION+ALE method.

• Element Deletion.zip contains the files for the proposed Element Deletion Method.

Google Drive Link to download the code:

https://drive.google.com/open?id=1aYEiKHie0rUTHCKWO7fjh_B0pHfCyEu2

Note: The element deletion codes were removed from this site. Please send me an email to request the code package!

Publication List:

• Y. Wang & O. I. Zhupanska (2018). Modeling of Thermal Response and Ablation in Laminated Glass Fiber Reinforced Polymer Matrix Composites Due to Lightning Strike, Applied Mathematical Modelling, Vol. 53, pp. 118-131.

• Y. Wang & O. I. Zhupanska (2015). Lightning Strike Thermal Damage Model for Glass Fiber Reinforced Polymer Matrix Composites and its Application to Wind Turbine Blades, Composite Structures, Vol. 132, pp. 1182-1191.

• Y. Wang & O. I. Zhupanska, Thermal Ablation in Fiber-Reinforced Composite Laminates Subjected to Continuing Lightning Current, 2016 SCITECH/AIAA/ASCE/AHS/ASC Structures, Structural Dynamics & Materials Conference, San Diego, CA, 2016.

• Y. Wang (2017). Multiphysics Analysis of Lightning Strike Damage in Laminated Carbon/Glass Fiber Reinforced Polymer Matrix Composite Materials: A Review of Problem Formulation and Computational Modeling, Composites Part A, Vol. 101, pp. 543-553.

• O.I. Zhupanska & Y. Wang, Modeling of Lighning Strike Effects in the Fiber-Reinforced Polymer Matrix Composites. 2018 AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference (p. 1465).