Impact, damage

Many of the inspection problems posed by composites can be dealt with effectively by ultrasonic. Delaminations, bonding defects, impact damage, cavities and porosities are among the typical defects which can de detected by ultrasonic inspection. 

Impact resistance is determined usiag flyer plate impact tests, long rod impact tests, Hopkinson bar tests (50), and the Hquid jet technique (51). Impact damage resistance is often quantified by measuring the postimpact strength of the ceramic. 

A. M. Rajendran and W. H. Cook, "A Comprehensive Review of Modeling of Impact Damage in Ceramics," Joint report between the University of Dayton Research and the Air Force Armament Eaboratory, AFATL-TR-88-143 SBI-AD-E801 843, 99 pp., Dec. 1988. 

Impact damage Damage caused by the impact of a 25 mm diameter hemispherical impactor with 135 J of kinetic energy, or with that kinetic energy required to cause a dent 2.5 mm deep, whichever is least. 

There are, of course, many more aspects of composite hardware design that differ from metallic bonded structure but do not necessarily involve adhesive bonding. For instance there are many types of reinforcement tape and fabric to choose from, the orientation of the plies must be chosen, the ply stackups must be balanced to avoid part warping after cure, a minimum number of plies must be used to prevent non-visible impact damage that significantly affects the load carrying capability of the part, etc. 

This has a very high resistance to impact damage, even at subzero temperatures. It has good creep strength in dry conditions up to 115°C but degrades by continuous exposures to water hotter than 65°C. It is resistant to aqueous solutions of acids, aliphatic hydrocarbons, paraffins, alcohols (except methanol), animal and vegetable fats and oils, but is attacked by alkalis, ammonia, aromatic and chlorinated hydrocarbons. 

Impact damage Damage caused to lungs, surfaces of ductwork, or fans by particulate matter. 

Leak Deterioration Erosion Corrosion Impact damage Vibration Low pressure Low liquid level... 

Volume III. Warhead , AFATL TR-67-13-Vol-3 (1967) (Conf) E) L. Aemow J.J. Piechocki, Multiple Fragment Impact Damage Study , DA-18-017-AMC-3447 (A) (1967) (Conf) F) R.E. Vincent, Scaled Prototype Warhead Study for Dragon (Medium Anti-Tank/ Assault Weapon-Maw) , DRD-15 (1967) (Conf) G) W.H. Snyder C.R, Hoggatt, Performance... 

Exposure calculation to the emission calculations involving impact of emissions on humans and ecosystem of the emissions means the impact calculation of the dose from the increased concentration. The impact calculation is followed by calculation of impacts (damage in physical units) from this dose, using a dose-response function. The impact of WEEE substances on health and the environment is location specific and is based on conditional, that is to say the way the WEEE is taken care of. Hence, the exposure assessment relates to the population and the ecosystem being exposed to the externalities. 

Impact damage occurred to one of 48 10 kg polypropylene tubs of calcium hypochlorite, each closed with a polythene lid, all supported on a wooden pallet and stretch-wrapped round the base with polyethylene film. The spilled material was swept up and discarded, and the pallet was moved to another part of the warehouse, and some 30 mins, later flames were seen at the base of the pallet [1]. Ignition was attributed to contact between residual solid hypochlorite on the pallet and lubricant drips on the concrete floor from fork lift traffic. Application of a dry powder extinguisher had little effect on the fire, but use of a 40 1 water extinguisher led to rapid escalation of the fire as contact between hypochlorite... 

A. Impact damage, such as by cranes, road vehicles, excavators, machinery associated with the process... 

I ig. X.ll. Residual stillness a.s a funetion crack length as measured from double cantilever beam specimens after impact damage carbon fiber composites containing (O) unmodified epoxy ( ) rubber-... 

Bibo, G.A. and Hogg, P.J. (1996). A view, the role of reinforcement architecture on impact damage mechanisms and post-impact compression behavior. J. Muter. Sci. 31, 1115-1137. 

Caneva, C., Olivieri, S Santulli, C. and Bonifazi, G. (1993). Impact damage evaluation on advanced stitched composites by means of acoustic emission and image analysis. Composite Structures 25, 121-128,... 

Masters. J.E. (1987b). Characterisation of impact damage development in graphite/epoxy laminates. In Fractography of Modern Engineering Materials Composites and Metals, ASTM STP 948, ASTM. Philadelphia, PA, pp. 238-258. 

Poon, C., Benak, T. and Gould, R. (1990). Assessment of impact damage in toughened resin composites. Theor. Appl. Fract. Mech. 13, 81-97. 

Rechak, S. and Sun, C.T. (1990). Optimal use of adhesive layer in reducing impact damage in composite laminates. J. Reinforced Plasl. Composites 9, 569 582. 

Sun. C.T. and Rechak. S. (1988). Effect of adhesive layers on impact damage in composite laminates in Composite Materials Testing and Design (8th Conf.) ASTM STP 972 (J.D. Whitcomb ed.), ASTM, Philadelphia, PA, pp 97-123. 

Evans, A. G., M. E. Gulden, and M. Rosenblatt, Impact damage in brittle materials in the elastic plastic range, Proc. R. Soc., A361, 343-365 (1978). 

---