A novel hybrid experimental-numerical approach is proposed to determine the mixed-mode (I/III) dynamic fracture initiation toughness of engineering materials. To demonstrate the methodology, cylindrical aluminum alloy specimens with V-notch spiral cracks on the surface at spiral inclined angles of $${\beta _{sp}=0}^{\circ }, {11.25}^{\circ }, {22.5}^{\circ }, {33.75}^{\circ }$$ β sp = 0 ∘ , 11.25 ∘ , 22.5 ∘ , 33.75 ∘ and $${45}^{\circ }$$ 45 ∘ are subjected to dynamic torsion load using a torsional Hopkinson bar apparatus. The torque applied at the onset of fracture is measured through strain gages attached to the incident and transmitter bars. Stereo digital image correlation (StereoDIC) is performed to measure the full field deformation and crack mouth opening displacement (CMOD) as a function of loading time. Results are used to estimate the crack initiation time. The dynamic stress intensity factors are extracted numerically based on the dynamic interaction integral method using ABAQUS. The mode-I $$ {(K}_{Id})$$ ( K Id ) , mode-III $$(K_{IIId})$$ ( K IIId ) , and mixed-Mode ( $$K_{(I/III)d})$$ K ( I / I I I ) d ) dynamic initiation toughness data as a function of spiral angles are presented and discussed.

中文翻译：

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一种确定材料混合模式 (I/III) 动态断裂起始韧度的新方法

提出了一种新的混合实验数值方法来确定工程材料的混合模式 (I/III) 动态断裂起始韧性。为了证明该方法，圆柱形铝合金试样表面有 V 型缺口螺旋裂纹，螺旋倾斜角为 $${\beta _{sp}=0}^{\circ }, {11.25}^{\circ }， {22.5}^{\circ }, {33.75}^{\circ }$$ β sp = 0 ∘ , 11.25 ∘ , 22.5 ∘ , 33.75 ∘ 和 $${45}^{\circ }$$ 45 ∘使用扭转霍普金森杆装置来承受动态扭转载荷。在断裂开始时施加的扭矩是通过连接到入射杆和发射杆上的应变计测量的。执行立体数字图像相关 (StereoDIC) 以测量作为加载时间函数的全场变形和裂纹开口位移 (CMOD)。结果用于估计裂纹萌生时间。基于动态相互作用积分法使用ABAQUS对动态应力强度因子进行数值提取。模式-I $$ {(K}_{Id})$$ ( K Id ) 、模式-III $$(K_{IIId})$$ ( K IIId ) 和混合模式( $$K_{( I/III)d})$$ K ( I / III ) d ) 作为螺旋角函数的动态起裂韧性数据被呈现和讨论。