Polymer composites are widely used to store liquid chemicals. Recently, monitoring their structural health has attracted a lot of attention. The geometry of nanomaterial in polymer composites plays an important role in affecting the penetration progress, thus altering the durability of polymer composite. In this study, the silver nanocomposite-based structural health monitoring (SHM) sensors were designed to detect the progress of chemical diffusion and material degradation as a function of time. A comparison between the silver nanowire (AgNW) sensor and silver nanoparticle (AgNP) sensors was used to study the concentration and geometry of silver nanomaterial’s effect on acid penetration. It appeared that the structural health monitoring sensors’ resistance decrease in three stages with the diffusion time increase. Moreover, with the volume percentage of silver nanomaterial increase, the response time decrease. And the AgNW based sensors have shown a shorter response time. The conductive network that nanofillers formed in the sensors was studied its effect on the ion diffusion process. Modeling work based on Fick’s second law was conducted using MATLAB to study the geometry effect of silver nanoparticle, silver nanoparticle aggregate, and silver nanowire on acid penetration progress.