The objective of this investigation is to predict the natural frequency and specific damping capacity of laminated composite plates in various modes of vibration by using the finite element method.The simple definition of specific damping capacity is ψ = ΔU/U, where U is the maximum strain energy stored per cycle and ΔU is the energy dissipated per cycle. In this work, U is calculated by a finite element method which includes transverse shear deformation; ΔU is determined from a damped element model. The specific damping capacities, mode shapes, and natural frequencies of various free-free carbon and glass fibre-reinforced plastics plates have been predicted and measured.

A method for predicting the dynamic properties of laminated composite beams has been developed in this work.

No abstract

No abstract

In this study, a Sn–Bi composite solder paste with thermosetting epoxy (TSEP Sn–Bi) was prepared by mixing Sn–Bi solder powder, flux, and epoxy system. The melting characteristics of the Sn–Bi solder alloy and the curing reaction of the epoxy system were measured by differential scanning calorimeter (DSC). A reflow profile was optimized based on the Sn–Bi reflow profile, and the Organic Solderability Preservative (OSP) Cu pad mounted 0603 chip resistor was chosen to reflow soldering and to prepare samples of the corresponding joint. The high temperature and humidity reliability of the solder joints at 85 °C/85% RH (Relative Humidity) for 1000 h and the thermal cycle reliability of the solder joints from −40 °C to 125 °C for 1000 cycles were investigated. Compared to the Sn–Bi solder joint, the TSEP Sn–Bi solder joints had increased reliability. The microstructure observation shows that the epoxy resin curing process did not affect the transformation of the microstructure. The shear force of the TSEP Sn–Bi solder joints after 1000 cycles of thermal cycling test was 1.23–1.35 times higher than the Sn–Bi solder joint and after 1000 h of temperature and humidity tests was 1.14–1.27 times higher than the Sn–Bi solder joint. The fracture analysis indicated that the cured cover layer could still have a mechanical reinforcement to the TSEP Sn–Bi solder joints after these reliability tests.