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508                                    摩擦学学报(中英文)                                        第 45 卷


                h=0.2t                 σ 1 /σ ys  h=0.6t               σ 1 /σ ys                       σ 1 /σ ys
             (a)                Film     −6.64                  Film     −5.48  h=1.0t          Film    −4.76
                                                                                                        −2.69
                                         −4.96
                                                                         −3.51
                  Max: 8.45    Interface  −3.29  Max: 12.25   Interface  −1.54                Interface  −0.61
                                                                          0.43
                                                                                                         1.46
                                         −1.61
                                          0.07                            2.40   Max: 13.89              3.53
                               Substrate  1.74                Substrate   4.37                Substrate  5.60
                                          3.42                            6.34                           7.68
                                          5.09                            8.31                           9.75
                2 μm           t/R=0.08   6.77  2 μm           t/R=0.08   10.28  2 μm         t/R=0.08   11.82
                                          8.45                            12.25                           13.89
                                                                                            Max: 5.60
                 h=0.1t                σ 1 /σ ys  h=0.5t               σ 1 /σ ys  h=1.0t               σ 1 /σ ys
                                         −1.78
             (b)                         −1.47                           −1.65                          −1.74
                                                                         −1.08
                                                                                                        −0.93
                       Max: 0.96         −1.17
                 Film          Interface  −0.86  Film  Max:  3.47  Interface  −0.51  Film     Interface  −0.11
                                                                          0.06
                                                                                                         0.71
                                         −0.56                            0.63                           1.52
                                         −0.26                            1.19                           2.34
                               Substrate  0.05                Substrate   1.76                Substrate  3.15
                                          0.35                            2.33                           3.97
                4 μm           t/R=0.01   0.65  4 μm           t/R=0.01   2.90  4 μm          t/R=0.01   4.78
                                          0.96                            3.47                            5.60
                                        (c)  15  t/R=0.200  0.080
                                            Maximum principal stress, σ 1max /σ ys  9 6  0.0670  0.040
                                             12
                                                            0.050
                                                                        0.020
                                                                        0.010


                                              0 3                      0.005
                                               0.0  0.2   0.4  0.6   0.8   1.0
                                                       Indentation depth, h/t

               Fig. 6    Influences of the contact geometric parameter t/R on distributions and evolutions of film first principal stresses during
                            loading processes: distributions of the first principal stress with (a) t/R=0.08, (b) t/R=0.01,
                                      and (c) evolutions of the film maximum tensile principal stress
                             图 6    接触几何参数t/R对加载过程中薄膜主应力分布及演化的影响:(a) t/R=0.08,
                                  (b) t/R=0.01时膜基系统第一主应力分布和(c)薄膜拉伸主应力最大值
                15  (a)              0.067      1.0  (b)               0.067   15  (c) Ring cracking
              Maximum principal stress, σ 1max /σ ys  9 6  Film bottom 0.036 0.040  0.050 0.057  Critical depth, h 1max, c /t  0.6  Film surface  0.036 0.044  0.057  Critical stress, σ 1max, c /σ ys  9 6 3  (film surface)  0.036 0.044  0.057
                                                        h 1max, c /t=16.86 × t/R - 0.2123
                                                                                        σ 1max, c /σ ys =203.3 × t/R - 2.054
                                                0.8
                                                                               12
                12
                    σ 1max /σ ys =11.95 × h/t + 0.5642
                                                                                                      0.067
                                                                   0.050
                                                                                                  0.050
                                0.044
                                                               0.040
                                                0.4
                                                                                               0.040
                                                0.2
                3
                                                                                                (film bottom)
                0
                 0.0  0.2 t/R=0.02  0.6 Film surface 1.0  0.0 0.00  0.02  0.04  Film bottom   0 0.00  0.02  0.04 Radial cracking 0.08
                           0.4
                                                                                                   0.06
                                     0.8
                                                                   0.06
                                                                          0.08
                       Indentation depth, h/t       Contact geometric parameter, t/R  Contact geometric parameter, t/R
                 Fig. 7    Influences of the contact geometric parameter t/R on (a) transferring points of the maximum principal stressσ 1max ,
                            (b) transferring critical indentation depth h 1max, c , and (c) transferring critical stress σ 1max, c
                     图 7    接触几何参数t/R对薄膜的(a)拉伸主应力最大值σ 1max 位置转移点,(b)转移临界压入深度h 1max, c 和
                                                 (c)转移临界应力σ 1max, c 的影响
            断,在接触几何参数t/R=0.04条件下,膜基界面法向拉                       系统不会发生界面法向拉伸分层失效.
            伸分层的临界载荷与界面法向结合强度并非线性关                                 图9所示为接触几何参数t/R对膜基界面处最大法
              [14]
            系 ,并且当界面的法向结合强度大于0.9σ 时,膜基                         向拉伸应力演化的影响. 加载过程中,随着t/R的减小,
                                                  ys
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