Stress Distribution Changes of Fixed Jaw Plates When Processing Different Materials

The internal stress distribution of fixed jaw plates is directly affected by the physical properties of crushed materials. When the same jaw crusher processes cobblestone and granite, due to differences in material hardness, shape and crushing characteristics, the stress peak, concentration area and distribution uniformity inside the jaw plate will change significantly, which further affects the wear rate and failure mode of the component.

1. Changes in Stress Peak and Overall Load Level

Cobblestone has low hardness, moderate abrasiveness and mostly rounded shape. The crushing process is dominated by extrusion and grinding, with a small proportion of impact load. Correspondingly, the overall stress level inside the fixed jaw plate is low, the peak stress is mostly concentrated in the tooth surface contact area, and the value falls in the medium-low range of the material's allowable stress, so the base bears weak impact load. Granite has high hardness and strong abrasiveness, mostly with sharp edges and corners. It requires greater crushing force during operation, and the falling and crushing of materials are accompanied by strong impact loads. The internal stress peak of the jaw plate increases significantly, and the overall load level rises. The stress at positions such as tooth roots and section transition areas is more likely to approach the allowable upper limit of the material.

2. Changes in Stress Concentration Area and Distribution Morphology

When processing cobblestone, the contact area between the material and the tooth surface of the jaw plate is relatively large, the acting force is dispersed evenly, the stress distribution is gentle, and the concentration area is mostly located in the middle of the tooth surface. The stress gradient at positions such as tooth roots and back edges is small, with no obvious local stress mutation. When processing granite, the sharp edges and corners form multi-point contact with the tooth surface, resulting in high local contact stress. The stress concentration area shifts to the edge of the tooth crest and the corner of the tooth root, with uneven distribution and large stress gradient. Meanwhile, the stress concentration in the upper area of the jaw plate corresponding to the feeding impact point is more obvious, and fatigue cracks are prone to initiate at these positions during long-term operation.

3. Changes in Alternating Stress Cycle Characteristics

The cobblestone crushing process is continuous and stable. The alternating stress borne by the jaw plate has stable frequency and small amplitude fluctuation, which belongs to stable cyclic load, and the accumulation rate of fatigue damage caused by internal stress is slow. When crushing granite, due to the high hardness of the material, working conditions such as material jamming and instantaneous splitting are prone to occur during the process. The amplitude of alternating stress borne by the jaw plate fluctuates greatly, accompanied by superposition of instantaneous impact stress, which accelerates the accumulation of fatigue damage of internal stress, and may cause structural failure after long-term operation.

The differences in stress distribution corresponding to different materials require targeted matching in the material, tooth shape and wall thickness design of fixed jaw plates. General-purpose jaw plates can hardly meet the wear resistance and impact resistance requirements of multiple working conditions at the same time. Hunan Xiangjian Machinery Technology Co., Ltd. focuses on the field of mine wear-resistant parts, and can customize adapted fixed jaw plate products according to the types of on-site processed materials and equipment working conditions, so as to guarantee service performance and service life. For specific selection solutions, please visit the official website https://cn.xjgmg.com for consultation.