Safety of satellites as well as spacecrafts during space missions is a primary objective to preserve the physical and virtual assets onboard. Whipple shields belong to the class of protective equipment provided on the surface of the spacecrafts and satellites, to sustain impacts from the ultra-high speed debris, which can otherwise cause considerable damage to the corresponding structures. Recent works on whipple shields are focussed on determining the response of different geometrical arrangements and material properties under hyper-velocity impact at projectile speeds of 3-18 km/s. Advances in the whipple shield design include integrated and mechanised models employing high performance materials like fiber-metal laminates ensuring better operational capability. The forward bumper of the whipple shield is the first line of defence as it regulates the state of projectile after the primary impact. Use of aluminium alloys for front bumpers is popular, owing to their lightweight and strength characteristics. The advances for the front bumper have seen usage of ceramic, metallic foams, and super composite mixtures, which resulted in enhanced performance, durability and safety of the whipple shields. This work is a comprehensive coverage of the latest materials used for whipple shields, their performance characterization—both experimental and theoretical, and applications.

Elastomeric materials show promise as potential micro-fillers in brake linings. They can provide vibration damping and acoustic advantages in intermittent and abrupt impact applications such as braking. The elastomeric material can be salvaged from non-biodegradable automotive tires, thereby providing an opportunity to reuse materials that will otherwise be discarded in landfills. Both tribological and thermomechanical performances of the waste tire rubber were assessed to determine their potential for use as micro-fillers in the brake linings of commercial vehicles with a gross weight less than 16 tons. Accordingly, the brake lining materials were fabricated with fine waste tire rubber particulates (WTRPs) as the micro-fillers, phenolic-R resin as the binder, graphite as the dry lubricant, laterite as the co-filler, and coconut coir for natural fiber reinforcement. The effects of increasing the WTRP weight fraction on the brake response of the linings were analyzed, and the different compositions were benchmarked against a commercial brake lining. Mechanical characterization comprising compressive strength, hardness, density, and porosity studies were carried out. Frictional and wear characteristics of the linings were analyzed using a rotary tribometer with simultaneous thermal monitoring. The manufactured lining with 15 wt% WTRPs exhibited a mean friction coefficient of ~0.38, a specific volumetric loss rate of 1,662 µm³/(N·m), and improved thermal response. Using optical microscopy and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), wear surface morphology studies compared the relative development of primary and secondary plateaus and revealed the redistribution of wear debris, leading to the stability of the coefficient of friction.

Digital Image Correlation (DIC) is a vital optical measurement technique that finds diverse applications in the domain of mechanics of materials. In aerospace applications, DIC has excellent scope in structural health monitoring of aircraft components. Aircraft wings, one of the critical components are subjected to different loads during flight. Ground testing and In-flight testing of wings can benefit substantially by DIC monitoring. DIC can be utilized to analyze the time-based variation in the speckle pattern or grid, applied to the wing’s surface. High-resolution images processed through a suitable correlation software helps decipher the data into stress and strain contours. Thus, any potential material failure or component defects can be identified. DIC also finds a role in flutter analysis, enabling the scrutiny of wing vibrations and deformations. In this review, the applications of DIC in analysis of aircraft components has been taken up, as in-flight structural health monitoring is a critical activity for a safe flight.