An asymmetric laminate is employed to study impact-induced damage of subpenetration experiments. The configuration of the asymmetric laminate is chosen to have its stiffness characteristics almost identical to those of a symmetric laminate. The impact is made with a mild steel striker to have impact energy close to 12 J and impact velocity close to 50 m/s. A circular precrack is also introduced to facilitate failure on the midplane of a laminate. Due to material discontinuity at the midplane the damage area extension (DAE) of the precrack is found to be 1.83 cm~2 on asymmetric laminates against 0.73 cm~2 on symmetric laminates. Impact experiments are also conducted on bonded GFRP specimen with Epibond 1590 A/B adhesive using asymmetric laminates. DAE of adhesive interface is found to be substantially smaller than DAE of interlaminar failure. DAE of adhesive interface is further reduced when the adhesive is modified with 7.5% XNBR.
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机译：采用不对称层压板来研究冲击引起的次渗透实验损伤。选择非对称层压体的构造以使其刚度特性与对称层压体的刚度特性几乎相同。用低碳钢撞针进行冲击，其冲击能量接近12 J，冲击速度接近50 m / s。还引入了圆形预裂纹，以促进层压板中平面的破坏。由于中平面材料的不连续性，发现不对称层压板上预裂纹的损伤面积扩展（DAE）为1.83 cm〜2，而对称层压板上则为0.73 cm〜2。还使用不对称层压板，对带有Epibond 1590 A / B粘合剂的GFRP粘合样品进行了冲击试验。发现粘合剂界面的DAE明显小于层间破坏的DAE。当用7.5％XNBR改性粘合剂时，粘合剂界面的DAE进一步降低。
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