...AL Highsmith; FE Ledbetter; A Nettles; SS Russell In an effort to better understand the damage that develops in filament-wound composite structures when they are subjected to low velocity impact loads, a series of low velocity impact experiments was performed on small (146 mm (5.75 in.) diameter...

...WC Jackson; CC Poe, Jr The building block approach is currently used to design composite structures. With this approach, the data from coupon tests are scaled up to determine the design of a structure. Current standard impact tests and methods of relating test data to other structures...

...SA Salpekar Several two-dimensional finite element analyses of (0 2 /90 8 /0 2 ) glass/epoxy and graphite/epoxy composite laminates were performed to investigate some of the characteristics of damage development due to an impact load. A cross section through the thickness of the laminate with fixed...

... cracking and improve damage tolerance of the sandwich. Simply supported sandwich beam specimens were subjected to low-velocity, drop-weight impacts as well as high-velocity, ballistic impacts. The performance of the interleaved core sandwich panels was characterized by localized skin damage and minor...

...MS El-Zein; KL Reifsnider A new approach to the prediction of tensile strength after impact is presented. The method is based on the premises that the stress concentration associated with the constraint of the undamaged material around the impacted region dominates the remaining strength...

...C Kassapoglou; PJ Jonas; R Abbott The effect of low speed impact on the compressive strength of graphite/epoxy sandwich panels was examined experimentally and analytically. Various impactor sizes and impact energy levels were used. Impact damage was found to decrease the compressive strength...

...LW Gause; JM Alper The mechanical, impact, and fatigue properties of graphite/epoxy composites manufactured using a general braiding process are being evaluated for possible flight vehicle applications. This new process achieves a fully integrated, multi-dimensional orientation of the fibers...

...SP Joshi; CT Sun A systematic study of impact-induced fracture in a quasi-isotropic laminated composite is carried out. The main focus of the study is to understand damage initiation when a laminate is subjected to the impact of a foreign object. The total incipient damage of a laminate subjected...

...ED Reedy, Jr; TR Guess Compression, gas gun planar impact, and post-impact short beam shear test results are presented for a novel interlocked fabric reinforced Kevlar 49/epoxy composite. This material has roughly 4% fiber volume fraction in the through-the-thickness direction. For the purpose...

...KM Lal This work discusses a model to correlate the coefficient of restitution of low velocity transverse impacts of graphite-epoxy laminates with the residual deformation or central deflection at the end of the impact event. It is assumed that the energy absorbed by the target can be calibrated...

...MW Wardle; EW Tokarsky The instrumented drop weight impact test has been used to study the relative impact damage tolerance of Kevlar®-49 and Kevlar-29 aramid fibers, Thornel®-300 graphite fiber, and E-glass as reinforcements in epoxy-matrix composite materials. Under the conditions of the test...

...N Takeda; RL Sierakowski; LE Malvern Microscopic observations of cross sections of impacted [(0°) 5 /(90°) 5 /(0°) 5 ] glass/epoxy composite laminates have been made using a scanning electron microscope. The microphotos obtained have confirmed macroscopic observations such as the initiation...