Survey study for the causes of failure of plastic chairs using Finite Element Analysis

Plastic chairs find their wide application in social gatherings like church, parties, community meetings and even funerals. This is owing to their light weight thus easy for transportation. The plastic chairs are also available at affordable prices. Plastic chairs tend to fail without a warning while in service, injuring the chair occupant, sometimes severely depending on the place of accident and nature of fall. By considering loading of the chair by a person of average weight, forces acting on the chair were computed. The person is considered to be resting both arms on the arms of the chair and his back reclined on the back rest of the chair. Material type of the chair is Acrylonitrile Butadiene Styrene (ABS) which is an opaque thermoplastic and amorphous polymer. Taking the sitting chamber into consideration, the stress effects are spread across the plastic chair. The maximum stress experienced by the chair material is between 48.9MPa and 28MPa. With arms and sitting chamber taken into consideration, the stress effects are spread across the plastic chair including the legs, sitting chamber and back rest. The maximum stress experienced by the chair material is between 259MPa and very much below 12MPa. Deformation is the amount of stretching that an object undergoes due to the loading. The displacement will be distributed on the plastic chair and within the sitting chamber. The material experiences different displacement and with the least displacement as 1.786mm and the as 21.43maximum displacement as mm which occurs at the very center of the plastic chair. The Finite Element Analysis (FEA) was carried out and results were obtained and conclusions made. The recommendation given by the researchers should assist in reducing the risk of failure of the plastic chairs whilst in service.