碳(tan)(tan)纤维(wei)是含碳(tan)(tan)量(liang)高(gao)于(yu)90%的(de)无机高(gao)分子纤维(wei)。其(qi)中含碳(tan)(tan)量(liang)高(gao)于(yu)99%的(de)称(cheng)石(shi)(shi)(shi)墨(mo)纤维(wei)。碳(tan)(tan)纤维(wei)的(de)微观结(jie)构(gou)(gou)类似人造石(shi)(shi)(shi)墨(mo)，是乱层(ceng)石(shi)(shi)(shi)墨(mo)结(jie)构(gou)(gou)。碳(tan)(tan)纤维(wei)各层(ceng)面间(jian)的(de)间(jian)距(ju)约为3.39到3.42A，各平(ping)行层(ceng)面间(jian)的(de)各个碳(tan)(tan)原子，排列(lie)不如石(shi)(shi)(shi)墨(mo)那(nei)样规整，层(ceng)与层(ceng)之间(jian)借(jie)范德华力(li)连接在(zai)一起(qi)。
通常也把碳(tan)纤维的结(jie)构看成由(you)两维有序(xu)的结(jie)晶和孔洞组成，其中(zhong)孔洞的含量(liang)、大(da)小和分布对(dui)碳(tan)纤维的性能(neng)影响较大(da)。
当孔(kong)(kong)(kong)(kong)(kong)隙率(lv)(lv)低(di)于某个临界(jie)值时(shi)，孔(kong)(kong)(kong)(kong)(kong)隙率(lv)(lv)对碳(tan)纤(xian)(xian)维(wei)复合(he)材(cai)料的(de)层(ceng)间(jian)(jian)(jian)剪(jian)切强(qiang)(qiang)度、弯曲强(qiang)(qiang)度和(he)拉伸(shen)强(qiang)(qiang)度无明(ming)显的(de)影响。有些研究指出，引起(qi)材(cai)料力学性能(neng)下(xia)降的(de)临界(jie)孔(kong)(kong)(kong)(kong)(kong)隙率(lv)(lv)是(shi)1%-4%。孔(kong)(kong)(kong)(kong)(kong)隙体(ti)积含量(liang)在0-4%范围内时(shi)，孔(kong)(kong)(kong)(kong)(kong)隙体(ti)积含量(liang)每增(zeng)加1%，层(ceng)间(jian)(jian)(jian)剪(jian)切强(qiang)(qiang)度大约降低(di)7%。通(tong)过对碳(tan)纤(xian)(xian)维(wei)环氧树脂(zhi)和(he)碳(tan)纤(xian)(xian)维(wei)双(shuang)马来亚胺树脂(zhi)层(ceng)压板(ban)的(de)研究看(kan)出，当孔(kong)(kong)(kong)(kong)(kong)隙率(lv)(lv)超过0.9%时(shi)，层(ceng)间(jian)(jian)(jian)剪(jian)切强(qiang)(qiang)度开始下(xia)降。由试验得知，孔(kong)(kong)(kong)(kong)(kong)隙主(zhu)要分布在纤(xian)(xian)维(wei)束之间(jian)(jian)(jian)和(he)层(ceng)间(jian)(jian)(jian)界(jie)面(mian)处。并且孔(kong)(kong)(kong)(kong)(kong)隙含量(liang)越高，孔(kong)(kong)(kong)(kong)(kong)隙的(de)尺寸越大，并显著(zhu)降低(di)了层(ceng)合(he)板(ban)中层(ceng)间(jian)(jian)(jian)界(jie)面(mian)的(de)面(mian)积。当材(cai)料受力时(shi)，易沿层(ceng)间(jian)(jian)(jian)破坏(huai)，这也是(shi)层(ceng)间(jian)(jian)(jian)剪(jian)切强(qiang)(qiang)度对孔(kong)(kong)(kong)(kong)(kong)隙相对敏感的(de)原因(yin)。另外孔(kong)(kong)(kong)(kong)(kong)隙处是(shi)应力集中区，承载(zai)能(neng)力弱(ruo)，当受力时(shi)，孔(kong)(kong)(kong)(kong)(kong)隙扩大形成长裂纹，从而遭(zao)到破坏(huai)。
即(ji)使两种具有相同孔(kong)隙(xi)(xi)率(lv)(lv)的(de)(de)(de)层压板(ban)(在同一养护周期(qi)运用不(bu)同的(de)(de)(de)预浸方法(fa)和制(zhi)造方式)，它们也表现处完全不(bu)同的(de)(de)(de)力学(xue)行为(wei)。力学(xue)性能(neng)(neng)随孔(kong)隙(xi)(xi)率(lv)(lv)的(de)(de)(de)增(zeng)加而下降的(de)(de)(de)具体数(shu)值不(bu)同，表现为(wei)孔(kong)隙(xi)(xi)率(lv)(lv)对(dui)力学(xue)性能(neng)(neng)的(de)(de)(de)影(ying)响离散性大且重复性差。由于包(bao)含大量(liang)可(ke)变因素(su)，孔(kong)隙(xi)(xi)对(dui)复合材(cai)料层压板(ban)力学(xue)性能(neng)(neng)的(de)(de)(de)影(ying)响是个(ge)很复杂(za)的(de)(de)(de)问题。这些因素(su)包(bao)含:孔(kong)隙(xi)(xi)的(de)(de)(de)形状、尺寸、位置;纤维、基体和界(jie)面(mian)的(de)(de)(de)力学(xue)性能(neng)(neng);静态或(huo)者动态的(de)(de)(de)荷载。
相对于孔隙率和孔隙长宽比，孔隙尺(chi)寸(cun)、分布(bu)对力学性能的(de)影(ying)响(xiang)更大些(xie)。并发现大的(de)孔隙(面积>0.03mm2)对力学性能有不(bu)利(li)影(ying)响(xiang)，这归因于孔隙对层(ceng)间富胶区的(de)裂纹扩(kuo)展(zhan)的(de)产生(sheng)影(ying)响(xiang)。
碳纤维管(guan)(guan),玻璃纤维杆(gan)(gan), 碳纤维杆(gan)(gan) ,玻璃纤维管(guan)(guan)
