Strength Analysis of Steel Adhesive Double Lap Joints Reinforced by Rivets using FEA & Experimentation

Transcription

1 Strength Analysis of Steel Adhesive Double Lap Joints Reinforced by Rivets using FEA & Experimentation Mr. Gajanan M. Kulkarni 1, Prof. B. D. Gaikwad 2 1 PG Student, Solapur University, Solapur, M.S., INDIA 2 Associate Professor, Solapur University, Solapur, M.S., INDIA Author Correspondence: Address-Plot No-80, Hatture Nagar, Hotgi Road, Solapur, M.S., India , Telephone: gmkulkarni2020@gmail.com 1, bdgaikwad2008@rediffmail.com 2 Abstract Adhesive bonding is widely used for engineering application. Double lap joints are considered as a good category joint in variety of purposes. Here, investigation on double lap hybrid joint (consisting of Adhesive and Rivet both) is done for the vertical loaded MS Steel specimens. Overlapping length is varied along with two other factors viz. Number of rivets and adhesive composition (Resin to Hardner ratio). Finite Element analysis is done by using Ansys to see the nature of changes in the joint. Further validation by Mechanical testing is done by using Universal Testing Machine for Max. Stresses induced. Load-Stress relation obtained by Ansys results is approximately closer to experimental results. Percentage deviation is within permissible limit. Keywords Double Lap Joint, Finite Element Analysis, Hybrid Joint, Number of rivets, Overlapping Length, Resin to Hardner ratio, UTM Introduction Hybrid joints have a combination of adhesive bonding and mechanical fasteners. The advantage of using a combined bonded-riveted design is to enhance the joint strength. [1] It is generally accepted that an adhesively bonded joint is stronger than a mechanically fastened joint and a combination of these two named as hybrid joint is even stronger. [5] A Hybrid Joint combines multiple joining methodologies. A basic example is the bonded-and riveted joint. It has been found that it is possible to improve strength and fatigue characteristics of bonded joints through the inclusion of a single, or multiple, reinforcing rivets. [4] This paper illustrates the effect of changing the adhesive composition i.e. resin to hardner ratio, Number of rivets and overlapping length on the stresses induced in Steel Double Lap joint specimens. This analysis was carried out for only adhesive, only riveted and hybrid (adhesive and rivet) joints. 1

2 2. Finite Element Analysis The finite element method is a numerical analysis technique for achieving fairly accurate results to a wide variety of engineering problems. Although originally developed to study stresses in complex airframe structures, it has since been extended and applied to the broad field of mechanics. Because of its diversity and flexibility as an analysis tool, it is receiving much attention in engineering disciplines and in industry. [3] The ANSYS software has many finite element analysis capabilities ranging from simple, linear, static analysis to a complex, nonlinear, transient dynamic analysis. Any problem in ANSYS has to go through the three main steps build the model, apply loads, obtain solution and review the results. [2] The FEA stages using commercial tools are explained below: 3. FEA Methodology 3.1 Adhesive Joint (200 mm Overlap) Resin to Hardener Ratio = 1:1 (c) (d) Figure 1: Initial Process in FEA Adhesive Joint in ANSYS APDL Meshing Using Tet. 10 Node (c) Constrained at end face (All Dof=0) (d) Load Application Results: & Stress for above conditions are shown below 2

3 Figure 2: = 0.18 mm Max. Von Misses Stress (At kn) = Mpa Similarly results are obtained for adhesive with Resin to Hardener Ratio = 1.5:1 and 2:1 as follows Table 1: Results of Adhesive Joint for 200 mm overlap Sr. No. Resin to Hardener Ratio Force (kn) Stress (Mpa) 1 1: : : Rivet Joint (200 mm Overlap) Results: & Stress are shown below Figure 3: = 0.44 mm Max. Von Misses Stress = Mpa (at kn) 3.3 Hybrid Joint (200 mm Overlap) for Resin to Hardener Ratio = 1: Results: & Stress for above conditions are shown below 3

4 Figure 4: = 0.26 mm Max. Von Misses Stress = Mpa (at kn) Similarly results are obtained for Hybrid Joint with Resin to Hardener Ratio = 1.5:1 and 2:1 as follows Table 2: Results of Hybrid Joint for 200 mm overlap Sr. No. Resin to Hardener Ratio Force (kn) Stress (Mpa) 1 1: : : Adhesive Joint (300 mm Overlap) Resin to Hardener Ratio = 1: Results: & Stress for above conditions are shown below Figure 5: = 0.16 mm Max. Von Misses Stress (At kn) = Mpa Similarly results are obtained for adhesive with Resin to Hardener Ratio = 1.5:1 and 2:1 as follows Table 3: Results of Adhesive Joint for 300 mm overlap Sr. No. Resin to Hardener Ratio Force (kn) Stress (Mpa) 1 1: : : Rivet Joint (300 mm Overlap) using Single Rivet Results: & Stress are shown below 4

5 Figure 6: = 0.38 mm Max. Von Misses Stress = Mpa (at kn) 3.6 Hybrid Joint (300 mm Overlap) for Resin to Hardener Ratio = 1:1 using Single Rivet Results: & Stress for above conditions are shown below Figure 7: = 0.52 mm Max. Von Misses Stress = Mpa (at kn) Similarly results are obtained for Hybrid Joint with Resin to Hardener Ratio = 1.5:1 and 2:1 using Single Rivet as follows Table 4: Results of Hybrid Joint for 300 mm overlap using Single Rivet Sr. Resin to Hardener Ratio Force (kn) Stress (Mpa) No. 1 1: : : Rivet Joint (300 mm Overlap) using Double Rivet Results: & Stress are shown below 5

6 Figure 8: = 0.26 mm Max. Von Misses Stress = Mpa (at 53.7 kn) 3.8 Hybrid Joint (300 mm Overlap) for Resin to Hardener Ratio = 1:1 using Double Rivet Results: & Stress for above conditions are shown below Figure 9: = 0.29 mm Max. Von Misses Stress = Mpa (at kn) Similarly results are obtained for Hybrid Joint with Resin to Hardener Ratio = 1.5:1 and 2:1 using Double Rivet as follows Table 5: Results of Hybrid Joint for 300 mm overlap using Double Rivet Sr. No. Resin to Hardener Ratio Force (kn) Stress (Mpa) 1 1: : :

7 4. Experimental Work 4.1 Preparation of Specimen Mild Steel Plate having Carbon specification as C-15 (Carbon content 0.20 Max.) and Manganese in range % is selected for preparation of Experimental Specimens. Same material is used for Rivet. The Specimens are prepared for three types of joints viz. Adhesive, Rivet and Hybrid made up of Adhesive and Rivet. For all the specimens Dimensions are: Table 6: Dimensions of Specimen Used Sr. Dimensions Particulars No. 1 Length Width 50 3 Thickness 5 4 Overlapping Length 100, 200, 300 Adhesive (Resin to Hardner in Ratio) Number of Rivet 1:1 (By Volume) 1 Figure 10: Sample Specimen Before Test After Test 4.2 Experimental Set Up UTM-60 is used for testing the prepared specimens. 7

8 4.3 Experimental Results Figure 11: Experimental Set up Below table displays the results obtained in Joint Specimen test on Universal Testing Machine. Table 7: Experimental Results Sr. No. Type of Joint Overlapping Length Resin To Hardner Ratio Load Applied (kn) Obtained Max. Stress Obtained (Mpa) 1 only Adhesive 200 1: only Adhesive 300 1: only Rivet only Rivet Hybrid 200 1: Hybrid 300 1: Following sample graphs drawn for Load Vs. for 300 mm overlapping length 8

9 (c) Figure 12: Load Vs. Graphs for 300 mm overlap-1:1 Resin to Hardner ratio-single Rivet Only Adhesive Only Rivet (c) Hybrid 4.4 Validation of Results The numerical values of deformation and stress obtained in experimentation can be compared with FEA. Table 8: Validation of Results Sr. N o. Type of Joint Overlap ping Length Resin To Hardn er Ratio Load Appli ed (kn) Deformati on Obtained in FEA Obtained in Experimenta tion Stress Obtain ed in FEA (Mpa) Stress Obtained in Experiment ation (Mpa) Variati on (%) 1 only Adhesive 200 1: only Adhesive 300 1: only Rivet only Rivet Hybrid 200 1: Hybrid 300 1:

10 Figure 13: Comparative Charts Load Vs. Load Vs. Stress 5. Conclusion Maximum by computational & experimental methodologies are obtained in various cases as follows For Adhesive joint, the values are 0.18 mm & 0.19 mm respectively for 200 mm overlap For Rivet joint, the values are 0.44 mm & 0.46 mm respectively for 200 mm overlap For Hybrid joint, the values are 0.52 mm & 0.55 mm respectively for 300 mm overlap Maximum Stress by computational & experimental methodologies are obtained in various cases as follows For Adhesive joint, the values are Mpa & MPa respectively for 300 mm overlap For Rivet joint, the values are Mpa & MPa respectively for 300 mm overlap For Hybrid joint, the values are Mpa & MPa respectively for 300 mm overlap Variation in the computational & experimental analysis is ranges from 4% to 14% References [1] Raviraja S, L. Nafeez Ahmed, FEA and Experimental Evaluation of Bonded, Riveted and Hybrid Joints in Glass Fibre Epoxy Composite Laminates, International Journal of Innovative Research in Science, Engineering and Technology, Vol. 4, Special Issue 3, March 2015 [2] E.A.S. Marques, Lucas F.M. da Silva, M. Flaviani, Testing and simulation of mixed adhesive joints for aerospace applications, Composites Part B, Vol. 74, 2015, pp [3] Rohan P. Chumble, Prof. S. N. Shelke, Study of Effects of Adhesive Layer Thickness on Strength of Single Lap Joint by Using Ansys and Mechanical Testing, International Journal of Innovation in Engineering Research & Management, Vol. 01, Issue. 04, August 2014, pp.1-8 [4] V. K. Khemnar, Prof. S. B. Belkar, Prof. M. S. Mhaske, Swapnil S. Kulkarni, Evaluating the Shear Strength of A Hybrid Joint-Adhesive A Rivet For Potential Applications In Aerospace Industry, International Journal of Advanced Engineering Research and Studies, Vol. IV, Issue. I, Oct.-Dec. 2014, pp [5] T. Sadowski, M. Knec, P. Golewski, Experimental investigations and numerical modeling of steel adhesive joints reinforced by rivets, International Journal of Adhesion & Adhesives, Vol.30, 2010, pp

11 [6] Harald Osnes, Dag McGeorge, Experimental and analytical strength analysis of double-lap joints for marine applications, Composites: Part B, Vol. 40, 2009, pp A Brief Author Biography Mr. Gajanan M. Kulkarni 1 B.E. in Mechanical Engg., research in Design Engg., currently pursuing post graduation from Department of Mechanical Engg., SVERI s College of Engg. Pandharpur, Solapur University, Solapur, M.S., INDIA Prof. B. D. Gaikwad 2 M. Tech in Mechanical Engg., Extensive research in Design Engg., currently working as Associate Professor at Department of Mechanical Engg., SVERI s College of Engg. Pandharpur, Solapur University, Solapur, M.S., INDIA