Low-Velocity Impact Response of Thermally Graded Auxetic Graphene Origami Beams via a Meshfree Penalty-Based Formulation

Auxetic graphene origami (GOri) structures, characterized by their negative Poisson’s ratio, offer promising potential for advanced impact-resistant materials. This study investigates the low-velocity impact (LVI) response of thermally graded (TG) auxetic GOri beams using a meshfree penalty-based formulation. The beam kinematics are modeled via first-order shear deformation theory (FSDT), while nonlinear Hertz contact theory describes impact interactions. Impact dynamics equations are derived using the energy method and solved through the Moving Least Squares (MLS) approach, assuming irregular node distributions with maximal overlap in the collision region. Beam boundary conditions are enforced through a penalty method. Parametric analyses examine the effects of TG distributions, top surface temperature, GOri folding degree, and GOri weight fraction on the LVI response. Results indicate that increasing the nonlinearity of the TG profile enhances internal cooling, leading to higher peak contact forces and reduced transverse deflections. Elevated top surface temperatures reduce contact stiffness, increase beam compliance, and prolong impact duration. Variations in GOri folding degree and weight fraction show opposing trends: greater folding reduces maximum contact force but increases beam displacement, while higher weight fractions enhance impact resistance. These findings provide comprehensive insights into tailoring TG auxetic GOri beams for improved structural resilience under impact loading.