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Acta Mech 212, 215–217 (2010) DOI 10.1007/s00707-009-0256-2 V. A. Lubarda · A. Marzani Viscoelastic response of thin membranes with application to red blood cells: addendum Received: 29 September 2009 / Published online: 25 November 2009 © The Author(s) 2009. This article is published with open access at Springerlink.com In a recent paper [1] we presented a closed form solution to the problem of radial stretching of a viscoelastic hollow circular membrane under uniform tension applied over its internal boundary. The significance of this solution is that it can be used, in combination with the solution for a hollow membrane under uniform tension at both boundaries, to obtain the solution of a more general problem in which the membrane is loaded by different tensions at two boundaries. For example, in the analysis of the micropipette aspiration of the red blood cell, the tension on the internal boundary is induced by the micropipette suction pressure, while the tension on the external boundary is due to the internal pressure in the cell itself. Since this important generalization was not made in our original paper, we present it here, with a particular attention given to the loading combination in which the tension over the external boundary is adjusted, relative to the tension over the internal boundary, so that the entire membrane is under tensile state of stress, in both radial and circumferential directions, avoiding wrinkling due to the absence of its compressive strength. If a hollow circular membrane, with the inner radius R 1 and the outer radius R 2 , is under the tension p 1 = p + q over its internal boundary, and the tension p 2 = q over its external boundary, the radial and circumferential stresses in the membrane are σ r = σ + S and σ θ = σ − S, where σ = q − R 1 p R 2 R 1 , S = p R 2 − R 1 r 2 R 1 R 2 In the case of the viscoelastic constitutive model considered in [1], the isotropic and deviatoric strain compo- nents, = ( r + θ )/2 and e = ( r − θ )/2, are governed by the differential equations t ∗ e + e = t ∗ ˙ + R 2 m t ∗ p , p + 2 − R 2 r 2 R 2 k t ∗ 2K 2K 0 R 1 where (μ, μ 0 ) and (K , K 0 ) are the shear and areal elastic moduli of the membrane, m = 1 + μ/μ 0 , and k = 1 + K /K 0 . The time-parameters are t ∗ = η/μ and t ∗ = η/K , where η and η are the shear and areal coefcients of viscosity. V. A. Lubarda ( B ) Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093-0411, USA E-mail: vlubarda@ucsd.edu Tel.: 858-534-3169 Fax: 858-534-5698 A. Marzani Department of Structural Engineering, University of Bologna, 40126 Bologna, Italy