In this study, the total strain is assumed to be superimposition of mechanical and hygral strains.
|  | (5.113) | 
where,Β  Β is the hygral strain in laminate.Β The stress in global direction is given as
Β is the hygral strain in laminate.Β The stress in global direction is given as
|  | (5.114) | 
The resultant in-plane forces are given as
|  | (5.115) | 
where,
|  | (5.116) | 
is defined as the resultant in-plane forces per unit length due to hygral strains.
In a similar way, we can give the resultant moments as
|  | (5.117) | 
where,
|  | (5.118) | 
is defined as resultant moments per unit length due to hygral strains. Combining Equation (5.116) and Equation (5.118), we write
|  | (5.119) | 
The inverse of this equation is written as
|  | (5.120) | 

 
 