Functionally graded adhesives for composite joints

Environmental effects and economic analysis of adhesives: a review of life cycle assessment (LCA) and techno-economic analysis (TEA)

“…In 2011, Stapleton et al started an analytical study to explore the impact of the loading conditions on the effectiveness of grading and the alterations to the grading due to adhesive flow during manufacturing (Stapleton et al, 2012). They found that by reducing the grading of the modulus of the adhesives material, the peel stress concentration could be reduced; however, the actual application of such joints were still limited due to several concerns, such as by using functionally graded adhesives, the flow of the adhesive during manufacturing may change the shape of the grading and cause the grading to be ineffective (Stapleton et al, 2012).…”

Corotational Formulation for Bonded Joint Finite Elements

“…The local stress and strain vectors for the ith adherend,ˆi σ and ˆi ε , contain only the axial compenents of stress/strain in the x-direction, ˆi (18) where the adherend centerline displacements are a collection of centerline displacement vectors for each adherend layer given as (19) and the centerline displacement vector of adherend i is given as , , (23) Furthermore, since the deflections in the local, rotated coordinate system are considered small, the shape functions, N , derived for the linearly elastic case are used [7][8][9] . Using the shape functions for the linear case, the local strain and displacements in the rotated coordinate system are related by the equation  ε Bq (24) where B is defined as B = GN .…”

“…To address this problem, a bonded joint finite element has been created [6][7][8][9] . This joint element considers the adherends to behave like beams and the adhesive to be made up of a bed of shear on normal springs.…”

“…This formulation tracks the rigid body rotation of an element through a local rotational coordinate system, and considers the rotations and deformations measured with respect to this rotated frame of reference to be small. The main benefit of this formulation is that the previously implemented code for the small rotation problem [7][8][9] can be utilized in subsequent calculations. The element has 2N nodes located at the boundaries of the centerline of the plates (numbered as shown in Figure 1b), and the nodal displacements are defined as: 1 T iN    q q q q (1) where the superscript represents the adherend or plate, and American Institute of Aeronautics and Astronautics q q q q q q    q (2) refers to the horizontal, vertical, and rotational displacements of the left and right nodes in plate i respectively.…”

Fonksiyonel Olarak Kademelendirilmiş Modüllü Yapıştırıcı Bağlantıların Isıl Gerilme Analizi

“…Bu konu ile ilgili güncel olarak yapılan teknik literature aşağıda detaylandırılmıştır [25]. Stapleton ve diğerleri [26] fonksiyonel olarak kademelendirilmiş malzeme özelliklerine sahip yapıştırıcı ile birleştirilmiş bağlantılardaki ayrılamalara neden olan gerilme yığılmalarının azaltılmasının mümkün alacağını ifade etmişlerdir. Onlar pratik olarak yapıştırıcı katmanı-nın kademelendirilmesinin artan imalat komplikasyonları, imalat sırasında yapışkan akış nedeniyle kademelendirmedeki değişiklikler ve yükleme koşulları-nın değiştirilmesinin kademelendirmenin etkiliği üzerin-deki tesirini göstermişlerdir.…”