Investigation of Important Parameters in Residual Stress Determination in Isotropic Plates and Laminated Composites by Slitting Method

Subject Areas : Journal of Simulation and Analysis of Novel Technologies in Mechanical Engineering

محمود مهرداد شکریه ¹ , سعید اکبری رکن‌آبادی ²

1 - استاد، دانشکده مهندسی مکانیک، قطب علمی مکانیک جامدات تجربی و دینامیک، آزمایشگاه تحقیقاتی کامپوزیت، دانشگاه علم و صنعت ایران.
2 - دانشجوی کارشناسی ارشد، دانشکده مهندسی مکانیک، قطب علمی مکانیک جامدات تجربی و دینامیک، آزمایشگاه تحقیقاتی کامپوزیت، دانشگاه علم و صنعت ایران.

Received: 2015-09-29 Accepted : 2015-09-29 Published : 2011-06-22

Keywords: Slitting Method, Residual stresses, Polymer Composites, Compliance Coefficients, Inite Element Analysis,

Abstract :

In the slitting method, a small width slit is created incrementally through the thickness of the stressed specimen and the released strains in each increment are recorded by a strain gauge. Compliance coefficients relate the measured strains to the residual stresses. This paper investigates the important parameters influencing the calculation of compliance coefficients for isotropic plates and laminated composites by finite element analysis. First, the process of slitting in isotropic materials is simulated using two and three-dimensional finite element models. The results show complete agreement between these two models. Calculation of average strain at the strain gauge location is necessary for the calculation of compliance coefficients. For this purpose, strain-based and displacement-based methods are used. In addition, the effect of slit width on compliance coefficients is checked. Then, released strains by strain gauges with different gauge-lengths are compared with each other. The results show that the strain gauges with smaller gauge-lengths can record higher values of released strain and consequently increase the precision of measurements. Lastly, compliance coefficients for two glass/epoxy and carbon/epoxy laminates are calculated using the proposed three-dimensional model.

References:

[1] Gascoigne H.E., Residual Surface Stresses in Laminated Cross-Ply Fiber- epoxy Composite Materials, Experimental Mechanics, 34:1, 1994, pp. 7-36.

[2] Ersoy N., Vardar O., Measurement of Residual Stresses in Layered Composites by Compliance Method, Journal of Composite Materials, 34:7, 2000, pp. 575–598,

[3] Vaidyanathan S., Finnie I., Determination of Residual Stresses from Stress Intensity Factor Measurements, Journal of Basic Engineering, 93, 1971, pp. 242-246.

[4] Cheng W., Finnie I., A Method for Measurement of Axisymmetric Residual Stresses in Circumferentially Welded Thin-Walled Cylinders, Journal of Engineering Materials and Technology, 107, 1985, pp.181-185.

[5] Cheng, W., and Finnie, I., Measurement of Residual Hoop Stress in Cylinders Using the Compliance Method, Journal of Engineering Materials and Technology, 108, 1986, pp. 87-92.

[6] Kang K.J., Song J.H., Earmme Y.Y., A Method for the Measurement of Residual Stresses Using a Fracture Mechanics Approach, J. Strain Anal. Eng. Des., 24, 1989, pp. 23-30.

[7] Schajer G., Prime M.B., Residual Stress Solution Extrapolation for the Slitting Method Using Equilibrium Constraints, Journal of Engineering Materials and Technology, 129, 2007, pp. 227-232,

[8] Prime M. B., Plasticity Effects in Incremental Slitting Measurement of Residual Stresses, Engineering Fracture Mechanics, 77:10, 2010, pp. 1552-1566.

[9] Prime M.B., Residual Stress Measurement by Successive Extension of a Slot: The Crack Compliance Method, Journal of Applied Mechanics, 52: 2, 1999, pp. 75-96.

[10]            Hermann R., Crack Growth and Residual Stress in Al-Li Metal Matrix Composites Under Far-Field Cyclic Compression, Journal of Materials Science, 30:15, 1995, pp. 3782–3790.

[11]             Prime M.B., Hill M.R., Measurement of Fiber-Scale Residual Stress Variation in a Metal-Matrix Composite, Journal of Composite Materials, 38: 23, 2004, pp. 2079-2095.

[12]             Hill M.R., Lin W.Y., Residual Stress Measurement in a Ceramic-Metallic Graded Material, Journal of Engineering Materials and Technology, 124: 2, 2002, pp. 185–191.

[13]             Lee M.J., Hill M.R., Effect of strain gage length when determining residual stress by slitting, Journal of Engineering Materials and Technology, 129:1, 2007, pp. 375-382.

[14]             ANSYS Help System, Analysis Guide and Theory Reference, Ver. 12.

[15]             Schajer G.S., Use of Displacement Data to Calculate Strain Gauge Response in Non- Uniform Strain Fields, Strain , 29:1, 1993, pp. 9-13,.

[16]             Shokrieh M.M., and Ghasemi A.R., Simulation of Central Hole Drilling Process for Measurement of Residual Stresses in Isotropic, Orthotropic and Laminated Composites Plates, Journal of Composite Materials, 41, 2007,  pp. 435-452.

[17]             Prime, M. B., and Hill, M.R., Uncertainty, Model Error, and Order Selection for Series-Expanded, Residual-Stress Inverse Solutions, Journal of Engineering Materials and Technology, 128, 2006,  pp. 175–185.