轻质点阵结构在结构轻量化、承载、吸能、隔热、减震等领域都有着巨大的应用前景。点阵结构的构型设计与制备是当前点阵结构研究与应用的焦点与难点，增材制造技术的出现在填补传统点阵结构制备工艺短板的同时，也带来了各向异性和支撑材料去除等问题，本文从制备工艺出发，提出了将嵌锁组装工艺与增材制造技术相结合的方法来进行点阵结构的制备，成功解决了一体化打印点阵结构中存在的问题，显著提升了点阵结构的力学性能和制备效率。然后采用嵌锁组装制备方法开展新型点阵构型的设计，通过利用点阵结构在外载荷作用下杆件的特殊变形行为，来对新型点阵结构的超常力学行为进行研究。

针对熔融沉积成型（FDM）技术一体化打印的点阵结构中由纤维分布造成的各向异性问题和支撑去除问题，本文首次将嵌锁组装工艺引入FDM技术中，制备了相对密度为2.1%-8.3%的拉压主导BCC点阵结构，实现了FDM点阵结构中熔融纤维的最优分布状态，并且彻底解决了支撑去除的问题。通过与一体化打印的点阵结构开展对比研究，发现采用嵌锁组装制备的FDM点阵结构的表面粗糙度降低了80%，面外压缩强度和模量分别提升了37.6%-65.3%和11.4%-39.6%，同时能量吸收性能也提升了67%-270%。最后基于杆件的弹性屈曲、非弹性屈曲和塑性屈服三种失效模式建立了BCC点阵结构理论预测模型，实验值与弹性屈曲和非弹性屈曲预测模型较为接近。

针对聚合物喷射成型（PolyJet）技术一体化打印的点阵结构中由杆件打印倾角造成的各向异性问题和支撑去除问题，将嵌锁组装工艺拓展到PolyJet打印技术中，制备了2×2×2多胞元的BCC、BCC-Z、FCC和octet四种典型的点阵结构，实现了点阵结构中所有杆件打印方向的最优化，并且无支撑去除问题。通过与采用PolyJet技术一体化打印的四类点阵结构进行对比，发现采用嵌锁组装法打印的时间和耗材均减小了80%以上，嵌锁组装BCC、BCC-Z、FCC和octet多胞元点阵结构的面外压缩强度分别提升了102.3%、121.9%、107.0%和105.5%，比吸能分别提升了129.4%、186.1%、72.5%和112.9%，其中嵌锁组装BCC-Z点阵结构的力学性能提升幅度最大。截面尺寸对PolyJet点阵结构的力学性能影响较大，随着杆件截面尺寸的增大，一体化打印点阵结构的失效模式更为突然和剧烈，而不同尺寸下嵌锁组装点阵结构在发生破坏时均产生了较大的杆件变形。随着杆件截面尺寸的减小，嵌锁组装点阵结构相较于一体化打印点阵结构的强度提升幅度越大。最后建立了四类点阵构型面外压缩载荷下基于杆件弹性屈曲、非弹性屈曲和屈服三种失效模式的理论模型，通过和实验值的对比验证了理论模型的准确性。

为实现轻质结构渐进吸能的力学性能，本文利用点阵结构压缩过程中构型的转化提出了一种应力应变曲线渐进上升、多级可控的蝴蝶型点阵构型，并且采用切割-嵌锁组装和真空钎焊工艺设计制备了稀疏型和致密型两类不同相对密度的蝴蝶型点阵结构，点阵结构的母材为塑性变形较好的304不锈钢。建立了两类蝴蝶型点阵结构构型转化下的理论模型，实现了多层级应力应变曲线各阶段的理论预测，开展了两类点阵结构面外压缩载荷下的实验和数值模拟研究，验证了构型转变实现应力应变曲线逐级上升、渐进吸能的可行性和理论模型的适用性。其中，致密型蝴蝶点阵结构的构型转变的稳定性更强。通过改变蝴蝶型点阵结构中竖杆的长度，实现了吸能曲线中各级应力平台幅值和长度的调节与控制。

开展了点阵构型设计与点阵结构超常力学行为之间关系的进一步探索，在蝴蝶型子构型的基础上提出了一种单个点阵胞元具有负泊松比效应的点阵结构，初步实验结果表明该弯曲主导的点阵构型实现了低密度条件下的高比吸能，填补了Ashby比吸能密度图谱中的空白。最后提出了一种能够在面外压缩载荷作用下实现屈曲驱动扭转的压扭点阵胞元，单胞结构的瞬时轴向应变的扭转角达到了150°/%。

Lattice structures have attracted much interest because of the various application potential in light-weight structures, load bearing, impact energy absorption, thermal management and damping. The configuration design and fabrication of the lattices are the focus and difficulty of application. The development of additive manufacturing (AM) technology provides the possibility for the fabrication of complex lattice structures, but also brings the problems of anisotropy and support material removal. A snap-fit method is introduced into the AM technology to solve these problems in additively manufactured lattices Then the new configurations are designed based on the snap-fit method and specific deformation to achieve rare and unpredictable mechanical performances of lattice structures.

The anisotropy in fused deposition modeling (FDM) lattices comes from the distribution of filaments in the struts. The snap-fit method is introduced into the FDM to fabricated the BCC lattices of polylactic acid (PLA plus) with relative densities ranging from 2.1% to 8.3%. This method makes it possible to deposit all the filaments along the length direction of the strut. The measured peak strengths, compressive

moduli and energy absorptions of the snap-fitted FDM lattices are improved by 37.6%–65.3%, 11.4%–39.6% and 67%–270%, respectively, compared with the conventional integrated FDM structures of the same relative density. Apart from improved mechanical properties, good surface quality and higher printing efficiency are also achieved in this method. Analytical models considering node volume are developed and able to predict the peak strengths and the compressive moduli of the snap-fitted FDM lattices.

A snap-fit method is introduced into PolyJet technology to fabricate polymer lattice structures with four typical configurations, namely BCC, BCC-Z, FCC and octet. Printing materials and printing time in this novel method are both reduced by over 80% compared to the conventional printing method. Uniaxial compression tests indicate that both the strengths and energy absorptions of all the four kinds of snap-fitted lattices are increased by over 100% compared to the integrated counterparts. The effect of strut thickness on compressive responses of the snap-fitted and integrated lattices is investigated. With the decrease of strut thickness, the advantage in the strength of the snap-fitted lattices becomes more obvious compared to the integrated counterparts. Ideal maximum strength models based on yield, elastic buckling and inelastic buckling are developed and are able to predict the compressive peak strengths of the snap-fitted PolyJet lattices.

Bending-dominated lattice structures namely butterfly lattices are proposed to achieve the multistage controllable stress-strain curve. A snap-fit method and vacuum brazing are used to fabricate two types of butterfly lattices with 304 stainless steel. The out-of-plane compressive experiments and finite element models are conducted to assure the stress-strain curves of the two kinds of butterfly lattices raise step by step since the reconfiguration process of the lattice under compression. The analytical models of each stage of the curve are developed and are able to predict the multistage mechanical performance. The butterfly type-2 lattices with higher densify trusses have a more stable reconfiguration process under compression. The butterfly type-2 lattices with different lengths of the vertical struts in the lattices are fabricated to adjust the value of each stage of the stress-strain curve. Stretch-dominated butterfly lattice strcutres are fabricated and the mechanical performance under compression are studied and compared with the bending-dominated butterfly lattices.

The relationship between the specific deformation of the struts in lattices and the unpredictable mechanical performance of the lattice is further studied. A novel bending-dominated lattice is designed to achieve the high specific energy absorption in a low density by utilizing the interaction between each strut. A twist lattice cell driven by buckling deformation under compression is proposed. The instantaneous twist per axial strain of the buckling-driven lattice is over 150°/%.