🤖 AI Summary
Gradient-based optimization fails in frame structural optimization due to mixed discrete cross-section types and continuous dimensional parameters. Method: This paper introduces Gumbel–Softmax reparameterization—first applied in structural optimization—to establish an end-to-end differentiable framework for hybrid variable modeling. It integrates gradient-driven joint topology/size optimization, automatic differentiation of finite element analysis, and probabilistic hybrid-variable representation, circumventing accuracy loss and computational overhead inherent in conventional enumeration or relaxation strategies. Contribution/Results: Across multiple benchmark examples, the proposed method achieves a 5.3× speedup over genetic algorithms and mixed-integer programming, improves optimal solution accuracy by 12.7%, and strictly satisfies structural safety requirements and design code constraints.