Finite Element Analysis of Neck Polymer Polymer Leg Stress

Finite Element Analysis of Nylon Polymer Polymer Chair Leg Stress WANG Hong, REN Fengming, YUAN Bing, ZHU Yanfeng (College of Construction, Guangdong University of Technology, Guangzhou 510643, China) The complexity of the stress distribution during stress is first performed. The data shows that when the computer leg is broken, the deformation is very small, showing a relatively obvious brittleness, and the average load is 1.5X104kN at the time of destruction. In the United States, the fractured surface of the leg is a rough surface. According to the fracture mechanics theory, it is inferred that the brittle failure is obvious.

The nylon polymer material was made into a standard test piece and its tensile strength was tested on a universal testing machine.

First, three finite element models were established to calculate: the original size model (abbreviated as the original model); the center outer ring was thickened with a 2mm model (abbreviated as the overall thickening 2mm); after calculation, a large number of calculation results were obtained, and The calculation results are basically consistent with the preliminary qualitative analysis. Based on the measured damage conditions, four points A, B, C, and D near the fracture were selected as the research object in the model, as shown. List the stress values ​​of various models under 1.5X104kN, as shown.

Table 1 shows the drop in the maximum stress after the model change. Table 2 shows the addition ratio of the model after the change.

Because the American specification requires that the appearance of the chair leg be the same, the original model is simplified, and the 10 ribs in the middle of the model are reduced to 5 ribs for comparison. The following three models were established for computational finite element analysis.

Simplified Original Size Model (Simplified Model for Short) Simplified Model Center Outer Ring Overall Thickening 2 (referred to as Overall Thickening 2mm) Table 1 Stress Comparison Table Model Maximum Stress/MPa Maximum Stress Drop/% Original Model 83.010 Thickened Table 2 Model Volume Comparison table model form model volume/mm3 volume increase/simplify the model center outer ring overall thickening 4mm model (referred to as the stress values ​​of various simplified models under 1.5X1tfkg effect as shown.

Table 3 shows the reduction ratio of the maximum stress after the simplified model change. Table 4 shows the addition ratio of the simplified model after the change.

4 Results Analysis After changing the size of the six models, due to the overall stiffness has been improved, the bearing capacity has increased to varying degrees, and the maximum stress is less than the ultimate strength of the material 82.585MPa, the material is in the elastic range.

The overall outward-thickening model has a greater increase in bearing capacity, and the maximum stress reduction ratio of up to 35% can meet the manufacturer's requirements. The large ratio of volume of 4.6% is also within the factory's allowable range.

Table 3 Simplified model maximum stress comparison Table 4 Simplified model volume comparison model form Maximum stress / MPa Maximum stress reduction /% Model form Model volume / mm3 Volume increase /% Original model inward thickening 2mm Inward thickening 4mm outward thickening 4mm 5 Conclusions The finite element method was used to simulate the computer leg and a three-dimensional finite element model was established. Through the calculation of Ansys and the analysis of the calculation results, the calculated results are in good agreement with the test results, which are basically consistent with the preliminary qualitative analysis, and verify the rationality of the force analysis of nylon polymer materials by Ansys software.