| The precision and ultra-precision processing technology is an important trend inthe development of modern science and manufacturing technology. Precision devicesof various types of micro-nano structures in the field of electronic information.Precision optics, biomedical,aerospace, defense has been more widely used, whilethe material is the material basis of the manufacture of these precision devices andstructure. Types of materials as well as by the composition of products during use bythe external load led to the deformation, damage, failure, damage, in order to ensurethe stability, reliability and durability of the tiny parts in the process of using, microand nano scale of the detection technology is particularly important to study themechanical properties of the material, it is directly related to the further research anddevelopment of micro and nano technologies.Nanoindentation testing technology is cutting-edge technology of engineering inrecent years, concern in the nanometer scale to measure hardness, elastic modulus,fracture toughness and other mechanical properties. Although the nano-indentationtechnique has made great progress and development in the test side, the test principle,calibration, etc., but to test the accuracy and credibility of the surface roughness andother factors will directly affect the test results. In this paper, we have researched thesample surface roughness on the nano-indentation test results through experimentaland finite element simulation analysis.This paper introduces the basic theory and methods of the nano-indentationtesting techniques firstly, and analysis of research on the basic principles of mechanicsinvolved in the nanoindentation test. Analyse the hardness, elastic modulus anddepth-load curve with different surface roughness of conductive glass measured bynano-indentation test. Confirmed that the sample surface roughness in thenano-indentation test can not be ignored, the sample surface roughness will reduce the accuracy of test results, the sample surface is more rough, the hardness and elasticmodulus of the test data is more scattered.Secondly, a simulation analysis has been carried out by finite element simulationsoftware called ABAQUS ideal flat aluminum (plastic material) and fused silica(elastic-plastic material)，we obtained the stress distribution in the equivalentdiagram, depth-load curve，and analyse the difference of the indentation simulationresults of the two materials. Aluminum simulation compared with experimental results,depth-load curve has showed a good coincidence, indicating that rationality of thefinite element simulation.Finally, we use the maximum height of the model contours as the assessment ofthe sample surface roughness parameters and introduce the horizontal distance betweenthe peaks and valleys of the contour of the angle between the D and the lowest valleyvertical and adjacent convex tangent by certain changes in the magnitude and the valueof D construct three-dimensional model of a certain surface roughness of the sampleand the sample model of the same surface roughness of different materials, simulationand analysis.The results showed that: exposure to the initial contact for the rough surface atthe peak, the maximum load and hardness test results than the deviation, for thesample of Rz=50nm, the indentation depth is about45nm, the largest deviation of theload test results, and then pressed into greater depth, the deviation of the load testresults decreases. The initial contact in the lowest point for a rough surface, themaximum load test results is too large. Pressure head pressure to the bottom, the edgeof the indenter with protruding the initial contact, the deviation of the maximum loadtest results is smaller than exposure to the initial contact for the highest peak andlowest valley deviation. The same indentation depth, roughness of the same sample,the deviation of the test results of the deviation of the material is fused silica sampletest results than the material is aluminum. |
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