- مبلغ: ۸۶,۰۰۰ تومان
- مبلغ: ۹۱,۰۰۰ تومان
A range of composite sandwich panels with different polymeric foam cores and face-sheets were subjected to full-scale air and underwater blast testing. The air blast panels had glass fiber reinforced polymer (GFRP) face-sheets with three different polymeric foam cores: styrene acrylonitrile (SAN), polyvinylchloride (PVC) and polymethacrylimide (PMI). The panels were subjected to 100 kg TNT equivalent charge from a stand-off of 15 m. The SAN panel had the lowest deflection and suffered from the least damage. The underwater blast panels had either a single density or graded density SAN foam core and either glass fiber reinforced polymer or carbon fiber reinforced polymer (CFRP) face-sheets. The research revealed that there is a trade-off between reduced panel deflection and damage. All the blast research that has been performed is part of a program sponsored by the Office of Naval Research (ONR).
Composite sandwich panels offer a number of advantages over traditional ship building materials including low radar signature, lightweight design, corrosion resistance and the combination of these factors to reduce fuel and maintenance costs. In naval applications the threat of an attack launched both at the surface and underwater is high, therefore the blast resistance of these composite sandwich panels is of high importance. Large scale composite sandwich panels with styrene acrylonitrile (SAN) foam cores were subjected to 30 kg C4 charges by Arora, Hooper and Dear . Polyvinyl chloride (PVC) foam is a common choice for composite sandwich panel cores. Hoo Fatt and Palla used analytical solutions to predict the response of a PVC foam core sandwich panel when subjected to blast loading . The low velocity impact behavior of composite sandwich panels with polymethacrylimide (PMI) foam cores was investigated by Shipsa and Zenkert along with the residual strength of the composite panels after impact . SAN, PVC and PMI are common foam polymer types that are finding application in composite sandwich panels and this research will investigate the air blast performance of these three materials.
The main conclusions drawn from this research are summarized in the following points:
- SAN foam polymer core has the lowest deflection and pull-out of the three polymer foams tested under air blast.
- The low deflection and pull-out of the SAN panel is a result of less damage as the stiffness of the panel is retained.
- Implementing a graded density SAN core reduces the panel deflection in underwater blast loading.
-There is a trade-off between reduced panel deflection and damage, an optimal combination needs to be identified.
6. نتیجه گیری
نتایج اصلی به دست آمده از این تحقیق به صورت نکات زیر جمع بندی شده اند :
• هسته پلیمری فوم های SAN کمترین انحراف و کشش از میان سه فوم پلیمری بررسی شده در شرایط انفجار هوا می باشد.
• انحراف و کشش کم پانل های SAN نتیجه خسارت کمتر حاصل از حفظ مقاومت پانل است.
• بکارگیری هسته های SAN با تراکم درجه بندی شده باعث کاهش انحراف پانل در بارگیری های انفجار زیر آبی می شود.
• رابطه ای بین کاهش انحراف پانل و خسارت ها وجود دارد و ترکیب بهینه باید شناسایی شود.