"成穹状弯曲" can be translated as "arch into a dome-like shape" or simply "dome-shaped bending" in English, depending on the context and the level of detail required.
"Arch into a dome-like shape" emphasizes the process of bending or curving to form a dome-like structure.
"Dome-shaped bending" is more concise and directly describes the resulting shape of the bending.