A key challenge in complex design problems that permeate science and engineering is the need to balance design objectives for specific design elements or subsystems with global system objectives. Global objectives give rise to competing design pressures, whose effects can be difficult to trace in subsystem design. Here, using examples from arrangement problems, we show that the systems-level application of statistical physics principles, which we term 'systems physics', provides a detailed characterization of subsystem design in terms of the concepts of stress and strain from materials physics. We analyze instances of routing problems in naval architectures, and show that systems physics provides a direct means of classifying architecture types, and quantifying trade-offs between subsystem-and overall performance. Our approach generalizes straightforwardly to design problems in a wide range of other disciplines that require concrete understanding of how the pressure to meet overall design objectives drives the outcomes for component subsystems.