Optimization of additively manufactured Ti-6Al-4V lattice structures for crashworthiness using topology and process parameter mapping

Project Abstract

This study presents a comprehensive investigation into the optimization of Ti-6Al-4V lattice structures manufactured via additive processes, with a focus on enhancing crashworthiness through topology optimization and systematic mapping of process parameters. The research addresses the critical need to balance energy absorption, weight reduction, and manufacturability in aerospace and automotive applications where impact performance is paramount. A multi-scale approach is employed, beginning with the design of lattice architectures guided by topology optimization to maximize specific energy absorption while maintaining structural integrity under dynamic loading. The lattice geometries explored include body-centered cubic, truncated octahedral, and novel hybrid foams, coupled with graded density distributions to tailor local stiffness and deformation mechanisms. Finite element modeling (FEM) is used to simulate quasi-static and dynamic crush simulations, capturing strain rate effects, progressive cell collapse, and energy dissipation pathways. Material behavior of Ti-6Al-4V is calibrated using experimentally derived constitutive models that incorporate yield, ultimate tensile strength, anisotropy, and rate-dependent plasticity, ensuring realistic responses under impact. Additive manufacturing process parameters—such as laser power, scan strategy, hatch spacing, and build orientation—are systematically varied to map their influence on porosity, residual stresses, surface roughness, and microstructural features that govern failure modes. A design of experiments (DOE) framework is adopted to identify robust parameter sets that maximize crash energy absorption while minimizing peak deceleration and weight. Experimental validation involves the fabrication of selected lattice specimens, followed by microstructural characterization using SEM and EBSD to correlate process-induced features with mechanical performance. Mechanical testing includes quasi-static compression to determine stiffness and energy absorption, followed by drop-weight and impact tests to quantify peak forces, mean crush strength, and energy dissipated per unit mass. Digital image correlation (DIC) is employed to capture full-field displacement and strain evolution during loading, enabling validation of computational models and identification of initiation sites for failure. The study extends to develop a predictive map linking topology, density distribution, and SLM/EBM process parameters to crashworthiness metrics, enabling rapid screening of design-parameter combinations for given weight and safety constraints. Results indicate that optimized graded lattices exhibit superior energy absorption with reduced peak deceleration compared to uniform lattices, while maintaining manufacturability within standard Ti-6Al-4V additive manufacturing limits. The role of process-induced porosity and surface roughness on fatigue life under cyclic loading relevant to rollover or repeated impact scenarios is analyzed, highlighting mitigation strategies such as post-processing and orientation control. Sensitivity analyses reveal critical interactions between laser power, scan strategy, and lattice topology that govern failure modes from shear buckling to cell-wall fracture. The research delivers a validated framework for integrating topology optimization with process parameter mapping to tailor crashworthiness, providing actionable design guidelines for engineers seeking high-performance, manufacturable lattice structures in safety-critical applications.

Project Overview

What This Project Is About

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The project looks at how tiny, lightweight structures made from a strong metal alloy (Ti-6Al-4V) can absorb impact better. It uses computer-guided design (topology) to arrange lattice walls and adjusts 3D printing settings (process parameters) to find the best balance between stiffness, strength, and energy absorption for crash scenarios.

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The Problem It Addresses

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Current crash parts are often too heavy or do not dissipate energy efficiently. The challenge is to create lattice structures that are both strong and light, while remaining reliable under repeated impacts. This project seeks practical designs and printing guidelines to improve safety and reduce weight in automotive or aerospace parts.

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Objectives of the Project

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1. Identify lattice designs that maximize energy absorption without excessive weight.
2. Explore how printing settings affect the printed lattice’s performance.
3. Develop a simple evaluation method to compare different designs.
4. Provide practical recommendations for designers using Ti-6Al-4V lattices.

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What You Will Do Step by Step

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1) Learn basic lattice concepts and topology optimization. 2) Create several lattice designs in a computer model. 3) Print samples with different processing settings. 4) Test samples to measure energy absorption and strength. 5) Analyze results to see which designs and parameters work best. 6) Present simple guidelines for future use.

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Expected Outcome

Clear recommendations on lattice geometry and printing settings that improve crashworthiness while keeping weight low. A straightforward comparison framework will be available for designers to choose between options based on safety and efficiency.