Metallic Microlattice Structures

This work reviews the current state of the art in metallic microlattice structures, manufactured using the additive manufacturing processes of selective laser melting, electron beam melting, binder jetting and photopolymer wave guides. The emphasis is on structural performance (stiffness, strength and collapse). The field of additively manufactured metallic microlattice structures is fast changing and wide ranging, and is being driven by developments in manufacturing processes. This book takes a number of specific structural applications, viz. sandwich beams and panels, and energy absorbers, and a number of conventional metallic materials, and discusses the use of additive manufactured metallic microlattice structures to improve and enhance these structural performances. Structural performances considered includes such non linear effects as plasticity, material rupture, elastic and plastic instabilities, and impact loading. The specific discussions are put into the contextof wider issues, such as the effects of realisation processes, the effects of structural scale, use of sophisticated analysis and synthesis methodologies, and the application of existing (conventional) structural theories. In this way, the specific discussions are put into the context of the emerging general fields of Architectured (Architected) Materials and Mechanical Metamaterials.

Inhalt

Preface.- 1. Introduction and overview.- 2. Some fundamental structural ideas for conventional metallic lattice structures.- 2.1. Lattice structures as a structural cellular material.- 2.2. General nomenclature for lattice structures.- 2.3. Lattice structures as core materials in sandwich panels .- 2.4. Impact energy absorption in metallic structures.- 2.5. Conclusions.- 3. Additive manufacturing processes and materials for metallic micro-lattices structures using selective laser melting, electron beam melting and binder jetting .- 3.1. Selective laser melting (SLM).- 3.2. SLM laser scan strategy and microstrut quality.- 3.3. Electron beam melting (EBM) process.- 3.4. Materials used in the selective laser melting and electron beam melting processes.- 3.5. Binder jetting (BJ) approach.- 3.6. Amorphous metals (metallic glasses).- 3.7. Additive manufacturing in metals using multiple materials.- 3.8. Conclusions.- 4. Parent material and lattice characterisation for metallic micro-lattice structures .- 4.1. Micro strut tensile tests (static).- 4.2. Micro strut tensile tests (dynamic).- 4.3. Micro lattice block characterisation (static and dynamic).- 4.4. Conclusions.- 5. Theory, simulation, analysis and synthesis for metallic micro-lattice structures.- 5.1. Finite element modelling beam elements.- 5.2. Finite element modelling solid element.- 5.3. Finite element modelling homogenised and continuum approaches.- 5.4. Analytic modelling of micro-lattice structures.- 5.5. Synthesis of micro-lattice topologies.- 5.6. More general approaches: Optimisation methods, use of voxels, multifunctionality.- 5.7. Lattice generation software.- 5.8. Conclusions.- 6. Photopolymer wave guides, mechanical metamaterials and woven wire realisation methods for metallic micro-lattices structures .- 6.1. Photopolymer wave guides .- 6.2. Woven metal wire.- 6.3. Conclusions.- 7. Applications for additively-manufactured metallic micro-lattices structures: core materials in beams and panels, energy absorbers (static and impact).- 7.1. Core materials in beams.- 7.2. Core materials in panels and wing sections.- 7.3. Energy absorption in solid and hollow strut lattices.- 7.4. Energy absorption in surface based lattices.- 7.5. Quantification of improvements in structural performance.- 7.6. Conclusions.- 8. Conclusions from the book: themes, future research strategies.- 8.1. The five themes.- 8.2. Some suggestions for future research.- 8.3. An alternative approach: the investigation of the design (property) space for selected structural applications.- 8.4. Overall conclusions from the book.