The Dynamic Impact Response of 3D-Printed Polymeric Sandwich Structures with Lattice Cores: Numerical and Experimental Investigation

This paper proposes a dynamic drop weight impact simulation to predict the impact response of 3D printed polymeric sandwich structures using an explicit finite element (FE) approach. The lattice cores of sandwich structures were based on two unit cells, a body-centred cubic (BCC) and an edge-centred cubic (ECC). The deformation and the peak acceleration, referred to as the g-max score, were calculated to quantify their shock absorption characteristic. For the FE results verification, a falling mass impact test was conducted. The FE results were in good agreement with experimental measurements. The results suggested that the strut diameter, strut length, number and orientation, and the apparent material stiffness of the lattice cores had a significant effect on their deformation behavior and shock absorption capability. In addition, the BCC lattice core with a thinner strut diameter and low structural height might lead to poor shock absorption capability caused by structure collapse and border effect, which could be improved by increasing its apparent material stiffness. This dynamic drop impact simulation process could be applied across numerous industries such as footwear, sporting goods, personal protective equipment, packaging, or biomechanical implants.

Other Innovation Policies and Alternative Modelling Approaches

This chapter discusses the macroeconomic impact evaluation of other policies related to innovation. In particular, two examples are shown on the impact simulation of a reduction to firms’ entry barriers and an increase in R&D tax credits. Alternative ways of modelling these two types of policy shocks are also provided to illustrate how different modelling platforms featuring different economic mechanisms can complement each other and enrich the landscape of macroeconomic policy impact assessments.

Simulation and Optimization of Body Structure of Electric Vehicles with Offset Collision

In recent years, as the rapid growth of the number of electric vehicles, people have more and more requirements on the safety performance of vehicles. However, compared with fuel vehicles, the structure of electric vehicles has its own particularity which makes the safety design of body structure more difficult. Thus, improving the passive safety of electric vehicles and protecting the passengers from injury in the collision to the greatest extent have become important issues for the automotive industry. This paper simulates the frontal offset impact simulation analysis of a certain type of SUV, and analyzes the safety performance of the vehicle from the perspective of member protection. The front side member structure and impact energy absorption which affect the passive safety of the whole vehicle are optimized and improved. The finite element model of the whole vehicle is rebuilt, and the frontal offset impact simulation test is carried out to verify the effectiveness of the optimization scheme.

Mechanical characterization of polyester resin composite with natural fibers

In this paper, composite materials reinforced with natural fibers were studied, such as: Jute (MC-RY) and Manta (MC-RM) as a proposal for new materials for the manufacture of a prototype for automotive defense. The materials were manufactured as laminates and characterized mechanically through stress, bending, impact and Brinell hardness index tests. The results indicated that both reinforcers improved the mechanical strength of the matrix by up to 71%, as well as the impact energy absorption by 14%. The mechanical properties for MC-RY determined in flexure (bending = 56 MPa, Eflection = 4.16 GPa and maximum = 14 mm) were used to perform an impact simulation in two different models created in SolidWork, the results indicated that the MC-RY could be used for the construction of the defense using 3 layers of this material.

Application of meshless methods to modeling of pistol bullets

The paper presents an analysis of applicability of two meshless methods to the modeling of pistol bullets on the example of a 9 mm Parabellum. The studies included the following methods: SPH and SPG. The results of computer simulations were confronted with ballistic test results in terms of shape-dimensional compliance of the deformed projectile. The relative error of the projectile diameter was 15 and 17% for the SPG and SPH methods, respectively. The deformation form for the SPH method deviated from the ballistic test results, while the SPG method faithfully reproduced the shape of the deformed projectile. Keywords: mechanical engineering, impact simulation, pistol bullet, SPH, SPG

Refrigeration of COVID-19 Vaccines: Ideal Storage Characteristics, Energy Efficiency and Environmental Impacts of Various Vaccine Options

This article considers the ideal storage conditions for multiple vaccine brands, such as Pfizer, Moderna, CoronaVac, Oxford–AstraZeneca, Janssen COVID-19 and Sputnik V. Refrigerant fluid options for each storage condition, thermal load to cool each type of vaccine and environmental impacts of refrigerants are compared. An energy simulation using the EUED (energy usage effectiveness design) index was developed. The Oxford–AstraZeneca, Janssen COVID-19 and CoronaVac vaccines show 9.34-times higher energy efficiency than Pfizer. In addition, a TEWI (total equivalent warming impact) simulation was developed that prioritizes direct environmental impacts and indirect in refrigeration. From this analysis, it is concluded that the cold storage of Oxford–AstraZeneca, Janssen COVID-19 and CoronaVac vaccines in Brazil generates 35-times less environmental impact than the Pfizer vaccine.