SBIR Phase I: A Novel System for Uniform Preload in Bolted Joints

该小型企业创新研究（SBIR）第一阶段项目的更广泛影响是开发适用于各种行业的改进螺栓紧固技术，包括可再生能源，发电，运输和基础设施。自19世纪引入现代紧固件以来，利用扭矩扳手的基本螺栓拧紧方法基本保持不变。这导致多螺栓连接中的预载荷变化高达30%。新的方法，包括预载传感，减少这种变化下降到15%，虽然在一个高成本。高预载荷变化导致接头效率低下、螺栓松动、螺栓断裂以及接头寿命期间的泄漏问题。所提出的创新可以将这种变化降低到5%，这是一个显著的改进。此外，与目前的四道次拧紧方法相比，它允许在两道次内拧紧多个螺栓接头，从而节省时间和劳动力。成功实施拟议技术将有利于降低能源成本，特别是在美国即将快速增长的海上风电。此外，它还将有助于防止核、石化、石油和天然气行业中的危险接头泄漏，并防止运输、基础设施和重型机械行业中的接头振动松动。拟议的技术将现有的广泛使用的技术（如扭矩扳手和超声波螺栓张力测量）与独特的专有计算机算法相结合。拟议的创新提供了螺栓张紧的精确控制，这对于多螺栓法兰接头的可靠性至关重要。基本概念已经通过高保真模拟得到了证明。在第一阶段的研究中，模拟研究将继续对更现实的多螺栓连接，以进一步验证算法。第一阶段研究的主要目标是实验验证和优化所提出的算法。在超声波预紧力传感器的帮助下，将对按比例缩小的法兰接头进行广泛的测试。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The broader impact of this Small Business Innovation Research (SBIR) Phase I project is the development of an improved bolt tightening technology applicable to a wide variety of industries including renewable, power generation, transportation, and infrastructure. The basic bolt-tightening method utilizing a torque-wrench has remained largely unchanged since the introduction of the modern fastener in the 1800s. This results in a preload variation of up to 30% in a multi-bolt joint. New methods, including preload sensing, reduce this variation down to 15% albeit at a high cost. High preload variation leads to inefficient joints, bolt loosening, bolt rupture, and leakage problems over the joint’s lifetime. The proposed innovation can potentially reduce this variation down to 5%, a significant improvement. Additionally, it allows multi-bolt joint tightening in just two passes compared to the current method of four passes which saves time and labor. Successful implementation of the proposed technology will be beneficial in reducing the cost of energy, in particular, offshore wind which is poised for rapid growth in the US. Additionally, it will help prevent hazardous leakage of joints in the nuclear, petrochemical, and oil and gas industries and prevent vibration loosening of joints in the transportation, infrastructure, and heavy machinery industries.The proposed technology combines existing, widely used technologies, such as a torque-wrench and ultrasonic bolt tension measurement, with a unique and proprietary computer algorithm. The proposed innovation offers precise control of bolt tensioning, which is essential for the reliability of multi-bolt flange joints. The fundamental concept is already proven through high-fidelity simulations. In Phase I research, simulation studies will continue on more realistic multi-bolt joints to further validate the algorithm. The primary goal of Phase I research is the experimental validation and optimization of the proposed algorithm. Extensive testing will be conducted on a scaled-down flange joint with the help of ultrasonic preload sensors. The secondary goal is the development of a minimum viable product concept based on this system.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.