Static and modal analysis of diaphragm spring used in micro depth sensing indenting Machine Niranjan Hiremath ⇑ , K.S. Tarun REVA University, RKP, Bengaluru 560064, India article info Article history: Received 12 October 2019 Accepted 18 October 2019 Available online 9 November 2019 Keywords: Diaphragm Modal analysis Resonance Indentation Depth Sensing abstract Indentation is perhaps the most commonly applied means of testing the mechanical properties of mate- rials. In a traditional indentation test (macro or micro indentation), a hard tip whose mechanical proper- ties are known (frequently made of a very hard material like diamond) is pressed into a sample whose properties are unknown. The load placed on the indenter tip is increased as the tip penetrates further into the specimen and soon reaches a user-defined value. This paper presents the analysis and testing of dia- phragm spring used in the Micro Depth Sensing Indenting Machine developed at Indian Institute of Science, Bangalore. Deflection of the spring are found out for various loads using ANSYS and results are validated through physical testing. Modal analysis of spring is carried out to find the possibility of resonance. Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Recent Research Emerging Trends in Materials & Mechanical Engineering. 1. Introduction A spring is basically an elastic body whose purpose is to deflect or distort under loading conditions and consequently absorb energy. Also they must regain their original shape after being deformed. Instrumented indentation also known as depth- sensing indentation is increasingly being used to probe the mechanical response of materials from metals to ceramics to poly- meric and biological materials. Christopher M. Stafford et al. [1] introduced an elegant, efficient measurement method that yields the elastic moduli of nanoscale polymer films in a rapid and quantitative manner without the need for expensive equipment or material-specific modelling. The tech- nique exploits a buckling instability that occurs in bilayers consist- ing of a stiff, thin film coated onto a relatively soft, thick substrate. N.Q. Chinh et al. [2] reviewed the phenomenon of plastic insta- bilities occurring in depth sensing indentation measurements. Researches presented focus on the characterization of Portevin– Le Cha ˆtelier type instabilities observed in different metal alloys during indentation. Adonias Ribeiro Franco Jr et al. [3] developed a computational routine based on Oliver- Pharr method for measuring a more pre- cise values of elastic modulus using a Fischerscope H100 – depth sensing indentation apparatus, with a Vickers indenter. This com- putational routine aims also to measure Vickers hardness, as the equipment does not have software for this purpose. From indenta- tion data it was possible to determine initial unloading stiffness, contact depth, projected contact area, reduced modulus, elastic modulus and Vickers hardness of materials. The validity of the rou- tine was verified analyzing two coatings and nine bulk specimens with different elastic–plastic behaviors. A. S. Maxwell et al. [4] developed a new technique following recent developments in impact excitation and depth-sensing indentation to measure the Poisson ratio of coatings. Impact exci- tation was first used to determine the Young modulus of the coat- ings. These results were then used in combination with the plane strain modulus obtained from depth-sensing indentation to deter- mine the Poisson ratio of the coating. This technique has been suc- cessfully applied to determine the Poisson ratio of sputter deposited TiN coatings up to 2.66 mm thick. Consistent values of Young’s modulus 42769 GPa and Poisson’s ratio 0.2360.03 were obtained for all the coatings, which agree with literature values for similar but thicker coatings obtained using acoustic microscopy. Even though, there have been many methods based on many dif- ferent approaches their complexity is still a challenge in measuring devices. In this paper, an attempt is made to design, develop and test diaphragm spring used in the instrumentation of depth sens- ing machines. https://doi.org/10.1016/j.matpr.2019.10.098 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Recent Research Emerging Trends in Materials & Mechanical Engineering. ⇑ Corresponding author. Materials Today: Proceedings 20 (2020) 161–166 Contents lists available at ScienceDirect Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr