Mechanical characterization of failure mechanisms during the cutting of Caragana korshinskii Kom. branches

The mechanical properties related to the failure of Caragana korshinskii Kom. branch is critically important for the design of stem crushers. This paper studies Caragana korshinskii Kom. branch, focusing on shear and transverse compression tests. When the external load surpasses the strength limit, the internal structure of Caragana korshinskii Kom. branch undergoes damage and cracking. As cracks accumulate, expand, and fuse, CKB deforms and fractures. The failure process is characterized by elastic, elastoplastic, and plastic fracture, indicating that the yield strength varies. The sampling position and moisture content significantly influence the maximum shear strength and compressive strength, with the sampling position being particularly impactful. Shear and transverse compression tests illustrate the development process of CKB. Additionally, second-order response models for the relationship of the CKB moisture content, sampling location, and loading rate with shear strength and compressive strength were constructed. The p-values of the models were all less than 0.01, with determination coefficients exceeding 0.98, adjusted determination coefficients over 0.96, and coefficients of variation being 8.78 and 6.51%, respectively. Furthermore, the shear failure range spanned from 37.25 to 158.94 MPa, and the compression failure range extended from 12.32 to 63.93 MPa. In summary, to achieve effective chopping of CKB, the applied force must exceed the maximum shear strength of 158.94 MPa and the compressive strength of 63.93 MPa.