Human Models and Mathematical Models

Multi Objective Optimization Approach for Biomedical Stent using Parametric Optimization

Stent deployment process and its long-term usage requires to meet multiple objectives like final stent diameters for cardiovascular disease treatments, and minimalistic plastic strain during the deployment to meet the fatigue life. Achieving an exact dilation diameter and maintaining minimal plastic strain values are mainly based on stent geometric design, cross section, material, amount of crimping and expansion diameter. This paper presents an effective stent finite element (FE) modelling and parametric optimization method using DEP MeshWorks stent rolling and parametric tools, LS-DYNA and LS-OPT optimization tools. Controllable design and deployment process parameters are considered for optimum random sampling using a Design of Experiments (DOE) approach, and using a parametric tool, designs are generated, on which analysis and optimization is performed using LS-DYNA explicit solver. The result is an optimum design solution which meets the required diameter criteria, without exceeding the minimal plastic strain limit, and within the foreshortening and flexibility limits.

Effect of side incubator padding on unrestrained child crash dummy under deceleration force

Nearly 20 million low birth weight and premature infants are born each year in developing countries, 4 million die within their first month due to unavailability of incubators and neonatal intensive care. Neonates and infants that require an inter-hospital transfer or ambulance/vehicle transfer in an incubator could potentially face fatal and catastrophic events, once subjected to negative acceleration. The main factor affecting the applied force due to the harsh braking or collisional accidents to the neonate/infant is the configuration of the restraining system. By eliminating the restraining system or having low residual strength seat belts the neonate or infant can experience lifelong injuries or even death. The interior of an incubator in case the restraining system fails must be designed to protect the occupant. In this paper, the effect of the paddings on the incubator wall against the unpadded wall is studied on a crash dummy using LS-DYNA software. The deceleration pulse, velocity, and displacement are validated by a sled test at Cranfield Impact Centre (CIC).