ANALISIS NUMERIK TEGANGAN DAN KEGAGALAN PADA SAMBUNGAN REKAT DENGAN PEREKAT AUKSETIK

• Main Author: Palma Puspaningtyas, Chatarina
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/66153
• Institution: Institut Teknologi Bandung

For almost a century, aluminum alloys have been used to manufacture various load-bearing aircraft parts. Their excellent strength-to-weight ratio, cost effectiveness, and manufacturability still warrant the use of aluminum alloys in the structures for coming decades. Joining aluminum parts can be effectively attained using adhesive, so-called adhesively bonded joints. A relatively large surface area of aluminum parts can be adhesively bonded to improve stress distribution, and to improve aerodynamic performance. One of the methods to enhance the joint performance (strength, toughness) is to tailor the adhesive. In this research, we explore the possibility of using a meta material adhesive by focusing on adhesive with negative Poisson’s ratio (auxetic). We develop 2D finite element models of single lap joints (SLJ) using cohesive elements within ABAQUS/Standard. The SLJ models with two different adhesive models are developed: (i) homogenous adhesive where Poisson’s ratio is prescribed as negative value; (ii) explicit adhesive where the negative Poisson’s ratio is achieved by prescribing numerous orthogonally-arranged elliptical microvoids. The objective is to evaluate the effect of using auxetic adhesive on peel and shear stresses in SLJ under tension, joint strength, and failure mechanisms. Upon validating the referenced SLJ model (model with positive Poisson’s ratio) using published experimental data with a good agreement, we further use the models to perform various parametric studies. Here, we show that our models could capture the crack propagation at the adherend/adhesive interface of the SLJ. The adhesive model with auxetic and explicit microstructure (orthogonally-arranged elliptical microvoids) could increase the joint strength by 44% as compared to that with positive Poisson’s ratio due to an increase of energy absorption by plastically-deformed ligaments at the interface. This thesis provides a feasible computational framework to further the promising path of using auxetic adhesive in the bonded joints of different materials, and subjected to more complex loading conditions.