The bulk properties of a material are governed by the internal particle arrangements. Nature has the luxury of arranging atoms into different morphologies that produce distinct properties among materials. The manipulation of atoms using human technology is both very expensive and inefficient. Fortunately, nanoparticles can be used to alter bulk material properties by varying their configuration inside materials. The self-assembly of nanoparticles is an effective method for organizing nanoparticles into designated arrangements, providing rapid and remote assembly with minimum human interference. Nanoparticles can either be preprogrammed to communicate with each other to form certain patterns under an external excitation, or be guided by external fields to assemble. The latter approach is relevant to the emerging development of additive manufacturing, broadening possibilities for material design. To fully utilize this facet of advanced additive manufacturing, a comprehensive understanding of material structure-property relationships is essential. However, precise control over particle arrangements using field-assisted assembly is still impractical. In this dissertation, a numerical approach using finite element analysis that explores the relationship between chainlike particle structures and material properties of elastomeric composites, specifically mechanical stiffness, electrical permittivity and thermal conductivity, is reported. With particles aligning into linear chains parallel to the mechanical loading direction, the bulk stiffness enhances 100-fold compared to the same composite with randomly distributed particles. Similar trends are observed for electrical permittivity and thermal conductivity. In contrast, when chains are aligned perpendicular to the direction of mechanical loading, applied voltage, or the heat transfer path, the influence of particle chains on these material properties is negligible. The introduction of zigzag chains provides intermediate results, offering granular modulation over the bulk properties. The mechanical stiffness, electric permittivity, and axial thermal conductivity decrease gradually with increasing zigzag angle, while the transverse thermal conductivity increases as this angle is increased. The electric permittivity also increases with interchain spacing, but decreases as interparticle spacing increases. When the filler volume fraction is lower than 9%, smaller particles contribute towards higher permittivity, while when the volume fraction is larger than 9%, the sample containing larger particles has a higher permittivity. To predict the anisotropic thermal conductivity of a composite consisting of particle chains, a modified empirical model that accounts for the effects of interparticle spacing and zigzag angle is proposed. Prospective research directions are discussed in the last chapter.