(裝甲兵工程學(xué)院 機械工程系，北京 100072)
摘 要: 利用過量綱理論和有限元模擬分析了Oliver-Pharr方法識別材料折合彈性模量的精度。結(jié)果表明：理論測試誤差明顯依賴于卸載后的殘余深度與最大壓入深度的比值(hf/hm)和材料的應(yīng)變硬化指數(shù)n。當(dāng)hf/hm＞0.7、n=0時，Oliver-Pharr方法計算的折合彈性模量最大測試誤差將近32%，其原因是由于估算得到的接觸深度明顯低于真實的接觸深度。在此基礎(chǔ)上，提出一種改進的計算方法，對接觸深度的估算進行修正，應(yīng)用改進方法確定材料折合彈性模量時，最大誤差可控制在±15%以內(nèi)。兩種鋁合金材料的壓入試驗也證明了此結(jié)論。
關(guān)鍵字: 納米壓入；彈性模量；量綱分析；有限元方法；硬化指數(shù)
（Department of Mechanical Engineering, Academy of Armored Force Engineering, Beijing 100072, China）
Abstract:The accuracy of reduced elastic modulus obtained by Oliver-Pharr method from nanoindentation data was analyzed by dimensional theorem and finite element simulation. The results show that the error depends on the final depth at the maximum depth ratio (hf/hm) and hardening coefficient (n) obviously. The maximum error is near upon 32% at hf/hm＞0.7 and n=0 because the predicted contact depth is lower than the true contact depth. Thereby, a modified method is brought forward to amend the predicted contact depth. The maximum error of reduced elastic modulus obtained by the modified method can be controlled within ±15%. The results of two indentation tests of aluminum materials agree well with the conclusion.
Key words: nanoindentation; elastic modulus; dimensional theorem; finite element method; hardening coefficient
