Which challenge arose when early Chinese crossbows using cast iron triggers attempted greater draw weights?

💡 Explanation

Higher draw weights exerted greater force on the cast iron triggers; work hardening was insufficient, so the dominant failure from yield stress became plastic deformation via shear. The soft cast iron couldn't withstand the shear stress, therefore, triggers failed increasingly often rather than functioning as intended, because stronger steels were not yet available.

• Which risk increases when constructing Roman fortifications using opus caementicium in regions prone to seismic activity?
• Which mechanism permitted 18th-century wooden ships to withstand hogging and sagging forces encountered in heavy seas?
• Which outcome occurred when Viking longships experienced significant swells?
• Which risk increases within complex Byzantine diplomacy involving royal marriages with foreign powers?
• Which effect consistently limited the agricultural productivity of Inca terraced farming at high altitudes?
• Which optical consequence results when an astrolabe’s alidade is misaligned with its sighting pinholes?