explicit constraint meaning in English

显约束的

The optimal model of truss structure is established , in which the cross sectional areas of bar are taken as design variables , the structure weight is taken as objective function . in the process , the reliability of structural displacement and bar stress and the fundamental frequency are taken as constraint functions . from the engineering practice , all the reliability constraints , which are implicit generally with the design variables , are equalized and transferred to the conventional explicit constraints
本文将主要考虑桁架结构的优化问题，首先建立数学模型，即以桁架的横截面积为设计变量、以重量最小为优化目标，位移、应力等可靠性及基频为约束条件；最后，从工程实际出发，对结构系统的可靠性隐形约束进行等价显化处理，使之转化为常规的横截面积优化问题。