CASE STUDY Detection and Quantification of Crack in Composite Mono Leaf Spring by Vibration Parameters Nagendra Iranna Jamadar 1 • Sangshetty Bheemanna Kivade 2 • Sudhakara Rao Pedada 3 Received: 13 January 2016 / Accepted: 23 May 2016 Ó The Institution of Engineers (India) 2016 Abstract Automobile industries focus for the components alternative to conventional materials with composites. There is high demand for enhanced performance and light weight. The emphasis is given for composite mono leaf spring as potential item as it is made up of glass fibre reinforced plastics despite they are sensitive to damages such as crack, delamination, de-bonding etc., occurred during either man- ufacturing or in service condition. These damages grow in progression and results in catastrophic failure. This work aims to deal with structural health monitoring to study and analyse the damage levels in composite mono leaf spring such as detection, location and quantification of damage. An experimental investigation has been carried out to evaluate presence and severity of damage by vibration parameters and validated with simulation. Keywords Composite mono leaf spring  Glass fibre reinforced plastic  Structural health monitoring  Vibration parameters Introduction Low cost and flexibility in structures during manufacturing process with composite materials has motivated significant growth in automotive field. The components made up of composites are less in weight and hence fuel efficient in vehicles. The materials do not rust or corrode like steel or aluminum. Consequently, automotive industries stress to reduce the overall weight of the vehicle by minimizing weight of every component in an assembly. Suspension leaf spring is also one of the potential items for weight reduction. The damage is the variation in geometrical properties of the structural components in the automotives. Damage propa- gates in three stages viz. initiation, growth and localization. The damage retards performance of either a component or structure or system. The composite materials are sensitive to the damages such as micro-cracks, micro-voids, inter-laminar de-lamination, de-bonding, and inclusions which are gener- ated during manufacturing or in service conditions. The crack is one of the invisible defects which are more critical in composite structures. When these structures are subjected to maximum or over loading during operating conditions then they are over stressed. Hence, nucleation of micro-cracks occurs in the structures. Environmental conditions and acci- dental events are too responsible for the enlargement of crack. The crucial issue of legendary automotive industries has been Structural Health Monitoring (SHM) during initial stage of damage detection. The unpredictable catastrophic failure of composite structures yields to infrastructure and support system losses. The SHM is the process to apply the damage inspection strategies to assess the current status of the structural components. Moreover, Non Destructive Testing (NDT) is the process of assessing the components or assemblies for discontinuities without destroying the parts or components or any system. The main disadvantage of NDT is piecewise inspection is not appropriate as the quantification and measurements of damage parameters cannot be assessed accurately. In situ inspection onsite is impossible in these processes. The SHM is suitable for remote area inspection of components in an assembly as & Nagendra Iranna Jamadar jamadar94@gmail.com 1 Visvesvaraya Technological University, Kalaburagi 585106, Karnataka, India 2 Basavakalyan Engineering College, Bidar 585327, Karnataka, India 3 Tata Technologies Ltd, Pune 411057, Maharashtra, India 123 J. Inst. Eng. India Ser. C DOI 10.1007/s40032-016-0315-0