Abstract representation of layered material with glowing stress lines.

Smarter Sticking: How New Material Tech Enhances Multilayer Performance

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Avery Sinclair in Tech & Innovation October 2026 • 5 min read.

"Spatial Tailoring of Adherends Boosts Strength in Additive Manufacturing"


In the world of materials science, creating structures with enhanced strength and durability often involves layering different materials. Multilayer materials are used in everything from aerospace components to electronic devices, and the key to their performance lies in how well these layers bond together. Traditionally, improving these bonds has focused on the adhesive layer itself, but a groundbreaking approach is shifting the focus to the layers being joined, known as adherends.

A recent study published in Scientific Reports explores a novel method: spatially tailoring the compliance and morphology of adherends using multimaterial jetting additive manufacturing (AM). This innovative technique allows for precise control over the material properties of the adherends, leading to significant improvements in the strength and performance of multilayer structures. Unlike previous methods that concentrate on modifying the bond layer, this research investigates how altering the adherends themselves can reduce stress concentrations and enhance overall durability.

This article dives into the details of this exciting research, explaining how multimaterial jetting AM enables the creation of customized adherends and examining the impact of this spatial tailoring on the mechanical performance of multilayer materials. We'll explore the methods used, the results achieved, and the potential applications of this technology in various industries.

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Multi-Material AM: Promise and Constraints

Multi-material additive manufacturing (MMAM) commonly means processing two or more materials within one additive process, for example by integrating multiple nozzles or vats loaded with different materials. Research on nature-inspired cellular metamaterials has often used a single material and offered limited multifunctionality; using multiple materials to create intricate geometries can add functionality, environmental adaptation, and improved mechanical properties. Reviews also identify limitations in software, processes, material choices, and joining mechanisms, particularly at interfaces between materials. Although combining materials in one part may overcome traditional fabrication and assembly limits, scaling the approach from laboratory work to industry remains a challenge.

Additive Manufacturing’s Evolution

Additive manufacturing’s history is described as a sequence of advances rather than a single invention. One account identifies progress in photopolymers, powder processing, extrusion, digital geometry, machine control, materials, and qualification as elements of that evolution. The modern industry emerged as these elements became reliable enough to produce repeatable physical parts directly from digital data. A broader historical review considers AM’s development alongside its emerging incorporation into major industrial and research sectors.

The Science of Stronger Layers: Tailoring Adherends with Additive Manufacturing

Abstract representation of layered material with glowing stress lines.

The central idea behind this research is that stress concentrations within the adhesive or bond layer often lead to the failure of multilayer structures. These stresses are most prominent near the edges of the adherends, where material properties abruptly change. While previous approaches have focused on optimizing the adhesive layer to distribute these stresses, this study investigates an alternative: modifying the adherends themselves to reduce stress buildup from the start.

Multimaterial jetting additive manufacturing (AM) makes this possible. This advanced 3D printing technique allows researchers to deposit and combine different materials with high precision, creating adherends with spatially varying properties. Think of it as creating a gradient of material stiffness within the adherend, rather than a sudden transition. This gradient is achieved by carefully controlling the composition of the adherend material during the printing process, using a combination of rigid and flexible polymers.

  • Compliance Tailoring: Adjusting the flexibility or stiffness of the adherend material in specific areas.
  • Morphology Tailoring: Modifying the physical structure or shape of the adherend to optimize stress distribution.
  • Anisotropic Design: Creating materials with different properties depending on the direction of applied force.
  • Layered/Sandwich Structures: Combining different materials in a layered arrangement to achieve specific mechanical properties.
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Printing Methods and Interface Design

Recent work on multimaterial systems spans commercial material-jetting platforms, including PolyJet3D, ProJet, and Connex3 Objet260. MultiJet Printing and Digital Material Jetting also enable multimaterial printing, while Two-Photon Lithography can reach sub-micron resolution but is limited by slow serial writing. Research on stepped-lap bonded joints examines geometrically graded interfaces, with the critical shear-lag length described as the minimum overlap needed to transfer an adherend’s tensile force across the bond layer in shear. These sources illustrate research attention to both printing capability and the geometry governing load transfer at bonded interfaces.

Limits and Failure Mechanisms

A study of multimaterial jetting reports that isotropic modulus tailoring of adherends produced only very small reductions in bondlayer stress, even at an E1/E2 ratio of 2000, for the sub-critical 50 mm bond length used in its experiments. A 2024 review emphasizes that understanding AM failure mechanisms is important for developing fatigue-resistant materials and improving component performance; it discusses tensile, fatigue, and fracture failures associated with microstructural heterogeneity. These findings caution that adding material or tailoring modulus does not by itself guarantee substantial stress reduction, while AM components can still be affected by multiple mechanical failure modes.

The researchers used numerical models to simulate the behavior of these tailored adherends under stress. These models revealed that adherend tailoring, particularly by reducing peel stress (the stress that pulls the layers apart), could significantly improve the performance of multilayer structures. The models also highlighted the importance of considering the bending stiffness of the adherends, which can influence stress distribution within the bond layer. In simpler terms, this method works by creating a more uniform distribution of stress across the entire joint, reducing the likelihood of failure at any single point.

Stronger Materials, Brighter Future: The Implications of Adherend Tailoring

The experimental results of this study confirmed the effectiveness of adherend tailoring. Multilayer samples created with tailored adherends exhibited significantly improved strength, toughness, and strain-to-break compared to baseline samples. Specifically, strength increased by 20%, toughness by 48%, and strain-to-break by 18%, while maintaining the stiffness of the multilayer structure. These findings demonstrate the potential of this approach to create stronger and more durable materials for a wide range of applications.

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Process Quality and Laminated Structures

Experimental research on laser powder-fed additive manufacturing examined how process parameters interact to improve the forming quality of Fe-Cr alloy multilayers on an AISI 4340 substrate. Separately, a 2024 review focuses on extrusion-based additive manufacturing of polymeric laminated structures made from multiple materials. Together, these sources point to two distinct research concerns: optimizing the formation of metal multilayers and reviewing extrusion approaches for polymeric laminates. The available source descriptions do not provide comparative performance results across these material systems.

Opportunities and Obstacles Ahead

A 2025 review of recent advances in additive manufacturing aims to synthesize current trends and assess future directions while considering both opportunities and obstacles. A separate market report, titled “2026 Additive Manufacturing Materials Market Outlook,” examines market dynamics, trends, future growth drivers, and challenges. Another source frames its outlook around 2026 and beyond, highlighting trends in 3D printing, AI, materials, and global production innovation. The source descriptions identify these as areas of attention but provide no specific market-size forecast or quantified growth figure.

While this study focused on sub-critical bondlengths, the researchers also suggest the benefits of adherend tailoring could be even more pronounced in systems with longer, critical bondlengths. Further research will likely explore this avenue, potentially unlocking even greater performance enhancements.

This research opens up new possibilities for designing and manufacturing high-performance multilayer materials. By focusing on the properties of the adherends and leveraging the capabilities of additive manufacturing, engineers can create structures with optimized stress distribution and enhanced durability. This technology could find applications in aerospace, automotive, electronics, and various other industries where strong and reliable bonding is critical. As additive manufacturing continues to advance, we can expect even more innovative approaches to material design and fabrication, paving the way for a future of stronger, lighter, and more durable products.

The study at a glance: tailored adherends in tensile-loaded multilayers

ComparisonBaseline multilayer[1]
Main outcomeMechanical performance, including failure[1]
Effect sizeStrength increased by 20%, toughness by 48%, and strain-to-break by 18%[1]
FundingAbu Dhabi National Oil Company (ADNOC), Award No: EX2016–000010[1]
Conflicts of interestThe authors declare no competing interests[1]
Times cited46[1]

The gains are measured against a baseline multilayer

  • 45%In numerical analyses, layered/sandwich adherends reduced peel stress by about 45% for the reported tailoring ratios, while shear-stress reduction remained below 3%.[2]
  • 47%For the experimental tailoring cases, the maximum peel-stress reduction was 47% with monotonic tailoring and 57% with non-monotonic tailoring.[2]

How adherend tailoring fits into bonded-joint research

Related work describes joint geometry as another route to optimization, while reviews and studies identify material-jetting platforms and other printing methods used for multimaterial fabrication.[3] [4] [5]

Later sources also frame additive manufacturing as a potential route to bonded systems at different length scales and cite this study as an example of multimaterial jetting for multilayer performance.[6] [7]

What the stress changes add up to

The approach changes the adherends next to the bond, rather than relying only on the bondlayer: increased compliance near overlap ends is intended to ease stress concentrations there.[2]

Taken together, the experiments link redistribution of bondlayer stress and strain with better multilayer performance, including greater toughness associated with increases in strength and displacement before failure.[2]

Where the evidence is weakest

  • The work used preliminary numerical analyses and parametric studies to select tailoring schemes; the reported stress reductions should be read in that context.[2]

What remains unresolved about tailored multilayers

  • Would the performance gains hold if the samples were printed in different orientations, rather than the single orientation used in this study?[1]
  • How do local interface properties in multimaterial systems shape the stress redistribution achieved by tailored adherends?[2] [8]
  • How readily can the approach move from research demonstrations to productive industrial use?[9]

Questions readers may have

Did the study test different tailoring profiles?

Yes. Its preliminary work examined constant, linear, quadratic, and exponential isotropic tailoring schemes.[2]

What was the experimental design trying to balance?

The selected high-performing case used a shorter tailoring length to reduce the likelihood of adherend failure and loss of multilayer stiffness.[2]

Sources

  1. Strength and Performance Enhancement of Multilayers by Spatial Tailoring of Adherend Compliance and Morphology via Multimaterial Jetting Additive Manufacturing (Springer Science and Business Media LLC, 2018)
  2. Strength and Performance Enhancement of Multilayers by Spatial Tailoring of Adherend Compliance and Morphology via Multimaterial Jetting Additive Manufacturing (Europe PMC, 2018)
  3. Multi-material additive manufacturing: a computational design perspective (2025)
  4. Switchable failure modes in architected lattice composites via processing-induced size-effect anomaly (2025)
  5. Enhanced strength and toughness of repurposed glass fiber reinforced adhesive joints for sewage applications (2023)
  6. A numerical study on stress mitigation in through-thickness tailored bi-adhesive single-lap joints (2023)
  7. Stress Distributions and Notch Stress Intensity Factors in Multimaterial V-notches Under Antiplane Shear and Torsion (2021)
  8. Properties and role of interfaces in multimaterial 3D printed composites (pmc.ncbi.nlm.nih.gov)
  9. Mechanical Strength of Additive Manufactured and Standard Polymeric Components Joined Through Structural Adhesives (pmc.ncbi.nlm.nih.gov)

About this Article -

Written with AI assistance from published research, and reviewed by the Mystum team. See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1038/s41598-018-31819-2, Alternate LINK

Title: Strength And Performance Enhancement Of Multilayers By Spatial Tailoring Of Adherend Compliance And Morphology Via Multimaterial Jetting Additive Manufacturing

Subject: Multidisciplinary

Journal: Scientific Reports

Publisher: Springer Science and Business Media LLC

Authors: Jabir Ubaid, Brian L. Wardle, S. Kumar

Published: 2018-09-11

Everything You Need To Know

1

What are multilayer materials and why are they important?

Multilayer materials are structures composed of multiple layers of different materials, crucial in various applications such as aerospace components and electronic devices. The effectiveness of these materials depends on the strength of the bonds between layers. This concept is central to the study of material science as it directly impacts durability and performance.

2

What does spatially tailoring of adherends mean, and how is it done?

Spatially tailoring of adherends involves using multimaterial jetting additive manufacturing (AM) to precisely control the material properties of the adherends. Instead of focusing on the adhesive layer, this method modifies the adherends themselves. This is done by creating a gradient of material stiffness within the adherend, using rigid and flexible polymers, to reduce stress concentrations. The implications include enhanced multilayer strength, better stress distribution, and the creation of more durable materials.

3

How does the article suggest improving the strength of multilayer materials?

The key to improving the strength of multilayer materials lies in modifying the adherends, not just the adhesive layer. By using techniques like multimaterial jetting additive manufacturing (AM), the compliance and morphology of the adherends are tailored. Compliance tailoring adjusts the flexibility or stiffness, morphology tailoring modifies the physical structure, and anisotropic design creates materials with direction-dependent properties. This approach reduces stress concentrations, leading to stronger and more durable bonds, which is a significant improvement over traditional methods.

4

What is multimaterial jetting additive manufacturing (AM), and how is it used?

Multimaterial jetting additive manufacturing (AM) is an advanced 3D printing technique that allows for the precise deposition and combination of different materials. This is used to create adherends with spatially varying properties. By carefully controlling the composition during the printing process, a gradient of material properties can be achieved, which is impossible with traditional manufacturing. This level of control is critical for tailoring adherends to reduce stress and enhance the overall performance of multilayer structures.

5

What are the benefits of using adherend tailoring in multilayer materials?

Adherend tailoring results in a significant improvement in the performance of multilayer structures. Experimental results showed that tailoring improved strength by 20%, toughness by 48%, and strain-to-break by 18%. These improvements highlight the potential of this method for creating stronger and more durable materials. These enhancements mean that the resulting materials can withstand greater stress and strain before failure, leading to longer lifespans and wider applications across industries. For example, imagine that you can improve the strength of an airplane wing, the wing becomes more resilient and safer.

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