论文标题
通过可区分的有限元求解器优化拓扑
Topology Optimization through Differentiable Finite Element Solver
论文作者
论文摘要
在本文中,利用自动差异化的拓扑优化框架通过通过完全可区分的有限元求解器来计算梯度来解决基于2D密度的拓扑优化问题的有效方法。提出了具有可区分物理求解器的优化框架,并在几个经典拓扑优化示例上进行了测试。可区分的求解器是在朱莉娅编程语言中实现的,可以自动以反向模式区分以提供每个操作的回调功能。然后可以通过使用链条规则来备份整个端到端梯度信息。该框架结合了一个由卷积层构建的生成器,并具有一组可学习的参数,以针对每种迭代提出新的设计。由于整个过程是可差异的,因此可以使用任何优化算法对生成器的参数进行更新,从而给定自动分化的梯度信息。提出的优化框架在设计半MBB梁时证明了这一点,并将其与有效的88线代码的结果进行了比较。通过仅更改目标函数和边界条件,它可以运行用于设计合规机理的优化,例如输出位移的力逆变器位于输入的相反方向。
In this paper, a topology optimization framework utilizing automatic differentiation is presented as an efficient way for solving 2D density-based topology optimization problem by calculating gradients through the fully differentiable finite element solver. The optimization framework with the differentiable physics solver is proposed and tested on several classical topology optimization examples. The differentiable solver is implemented in Julia programming language and can be automatically differentiated in reverse mode to provide the pullback functions of every single operation. The entire end-to-end gradient information can be then backed up by utilizing chain rule. This framework incorporates a generator built from convolutional layers with a set of learnable parameters to propose new designs for every iteration. Since the whole process is differentiable, the parameters of the generator can be updated using any optimization algorithm given the gradient information from automatic differentiation. The proposed optimization framework is demonstrated on designing a half MBB beam and compared to the results with the ones from the efficient 88-line code. By only changing the objective function and the boundary conditions, it can run an optimization for designing a compliant mechanism, e.g. a force inverter where the output displacement is in the opposite direction of the input.