Question

18.4. A mechanical adhesive has been designed for 10-year life at 60°C ambient temperature. Over time, the bond will degrade chemically and will eventually fail. The rate of the chemical reaction can be increased by testing at higher levels of temperature. Using an activation energy of Ea = 1.2 eV and the Arrhenius relationship, calculate the time-acceleration factors for testing at 120°C, 90°C, and 80°C.

Answer 1

aetigued for at 60'c aubieut tepesatale. Civen has beeu Amechorical adhesive eae Cactivation euergy) 12 e V To jiud ak facto Jor testig Time acceleraton foh mula used wuere c e LCv) autifiakle lfe measure L nepheseut a hepheseuttu hess leuel Cformulatd for teupesatune ound teperatur value absoluute vuik. 1 C in aue f 4ue uolel pataumetens deteruiued C >o). another moclel paramater to be cletemïne d to be activation energy activah'on eu esver1 Ea 0.617385x10 Vk Boltzmaun' coleut C e Vu VA Af LACcelerated CTe Vn jactor Af Accelehuh'en

Ea 12 ev 13925.3 3 814 K 8-617305K1VK at 20c factor or teati acccleanah'ou Time (Go273.1 K = 333.15K Vu Goc VA 12C = C120+273 -1s) K = 393.Ir K 13925.3314 39 3-15 333-IS e AF e G.379 Af = 589.33 e Time accelenah'cn jactor fum tes ting at 90'C (90273-5) k - 363. s K VA 13925.33014 315 363-1 Af e 31.6 Af = accele hah'u jactor jor tes h'ug at o c Time (80273. k = 353.k 3531S AF e lo 67 ime- accclehah'on jactor tor testing Heuce the ct 120 C,90'C aud o'c 99.33,31.6 aur d lo.67 are hepeck vey