The Experts below are selected from a list of 159 Experts worldwide ranked by ideXlab platform
D P Hess - One of the best experts on this subject based on the ideXlab platform.
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Threaded Fastener Locking With Safety Wire and Cotter Pins
Journal of Failure Analysis and Prevention, 2018Co-Authors: D P HessAbstract:This paper presents test results and analyses of safety lock wire and cotter pins with castellated nuts used as locking features in Threaded Fasteners. These mechanical components are used to secure hardware in aerospace and other applications as well as to assess whether a Fastener has been tampered with. Tests are performed on aerospace Threaded Fasteners. Locking moments up to safety lock wire and cotter pin failure are measured. Calculations of locking moment to failure are provided and compared to measured results. For Fasteners with safety lock wire, the angle of turn with applied moment is measured and computed. For Fasteners with cotter pins and castellated nuts, the angles of turn from clearances and applied moment are computed. Since both safety lock wire and cotter pin with castellated nut applications result in some angle of turn, analysis for loss of preload with angle of turn is developed. Calculations show modest loss in preload for typical angles of turn for long bolts, but a significant loss of preload is found for short bolts.
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Threaded Fastener secondary locking requirements
Journal of Failure Analysis and Prevention, 2017Co-Authors: D P HessAbstract:Secondary locking features in Threaded Fasteners are in widespread use in machinery, structures, and systems. In this paper, the mechanism for loosening of Threaded Fasteners is explained qualitatively and defined quantitatively in terms of the self-loosening moment inherent to Threaded Fasteners and external load-induced loosening moments. Equations for loosening moments are defined. This paper provides analysis which quantifies the locking action required to prevent loosening due to the inherent self-loosening moment and external load loosening moments in Threaded Fastener joints. This paper provides the basis and method for engineers to properly design or specify secondary locking features in Threaded Fasteners to provide sufficient locking and prevent loosening. Requirements for secondary locking feature moments are developed in terms of loosening moments and factor of safety. Test data and calculations are provided to substantiate the requirements. Examples are provided for common secondary locking features including prevailing torque and adhesive.
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direct verification of Threaded Fastener locking compounds and adhesives
Journal of Failure Analysis and Prevention, 2012Co-Authors: R Hunter, D P HessAbstract:This article explores the feasibility of a method to directly verify that thread lock compound or adhesive has cured sufficiently to provide secondary locking. The application of a torque after assembly and cure time was found to provide a viable verification test. Fastener material and coatings were found to significantly affect cure. For example, medium-strength anaerobic compound used with Fasteners made of inactive material such as stainless steel had curing issues which prevented determination of a useful verification test torque. However, modifications such as higher-strength compound or primer can be introduced making this method viable even for Fasteners made with inactive materials and coatings. This article outlines a process to implement this method in practice. This requires sample tests with representative product to determine a test verification torque. This process is particularly useful in identifying curing and locking performance issues, and provides guidance for modification so that the method can be successfully implemented in practice. Test results show that application of verification test torque with or without standard vibration test exposure does not degrade the locking performance.
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parametric study of Threaded Fastener loosening due to cyclic transverse loads
Engineering Failure Analysis, 2007Co-Authors: J A Sanclemente, D P HessAbstract:Abstract This paper presents results from an experimental investigation of mechanical loosening in bolted joints due to cyclic transverse loads. The influence on the resistance to loosening of basic parameters such as preload, Fastener material elastic modulus, nominal diameter, thread pitch, hole fit and lubrication is quantified. Sixty-four tests have been performed as part of a nested-factorial design in which the nominal diameter is the nesting factor of preload, thread pitch and hole fit. A statistical analysis identifies the factors and interactions that significantly affect the resistance to loosening and it is found that the preload and the Fastener elasticity are the most influencing parameters. A statistical model is developed that predicts the level of loosening reached by a Threaded Fastener under defined conditions. The analysis shows that optimum conditions to avoid Fastener loosening are high preload, low modulus of elasticity, large diameter, lubrication, tight fit and fine threads.
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three dimensional finite element analysis of Threaded Fastener loosening due to dynamic shear load
Engineering Failure Analysis, 2002Co-Authors: N G Pai, D P HessAbstract:Abstract The two most widespread causes of failure of Threaded Fasteners subjected to dynamic loads are fatigue and vibration induced loosening. This paper presents results of a study on failure of Threaded Fasteners by vibration induced loosening caused due to dynamic shear loads. Previous experimental work has revealed that Fastener loosening occurs as a result of complete or localized slip at the thread and head contact surfaces. A three-dimensional finite element (FE) model is used to study details of four different loosening processes that are characterized by either complete or localized slip at the head and thread contacts. The FE model is found to be capable of adequately modeling factors that influence slip and predicting the different loosening processes. Primary factors that influence slip at Fastener contacts are discussed. The results show that loosening can occur at relatively low shear loads due to the process of localized slip.
Lecronier David - One of the best experts on this subject based on the ideXlab platform.
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Compression Transmission Collar for Fastening
Digital Commons @ Kettering University, 2015Co-Authors: Atkinson Patrick, Lecronier DavidAbstract:A compression transmission collar apparatus (20) for implantation into a bone (22) with a hole (28) having a hole wall (32) comprising an intramedullary nail (34) defining a bore (40) and a Threaded Fastener (42) and a compression transmission collar (58) including an exterior face (64) and a top edge (60) and a bottom edge (62) and a first end (70) intersecting the top edge (60) at an acute angle and the bottom edge (62) at an obtuse angle and a second end (72) intersecting the top edge (60) at an obtuse angle and the bottom edge (62) at an acute angle and the first end (70) partially overlapping and opposing the second end (72) to define a slit (74) such that applying a compressional load to the top edge (60) causes the first end (70) to slide relative to and along the second end (72) causing the compression transmission collar (58) to compress axially and expand radially pressing the exterior face (64) against the hole wall (32)
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Easily Implantable And Stable Nail-Fastener For Skeletal Fixation And Method
Digital Commons @ Kettering University, 2013Co-Authors: Atkinson Patrick, Lecronier DavidAbstract:An intramedullary nail (20) defining a bore (34) is inserted into a medullary canal (26) of a bone (24). A Threaded Fastener (22) has a compression portion (48) presenting a compression portion diameter (D) and a Threaded portion (50) present ing a Threaded portion diameter (D). The Fastener (22) extends through a near cortex hole (40) and/or a far cortex hole (42), and the Threaded portion (22) Threadedly engages the bore (34). A compression transmission device (54) is disposed between a head (44) of the Fastener (22) and the intramedullary nail (20) for transmitting the compressional load of the Threaded Fastener (22) to the intramedullary nail (20). An interior space of the compression transmission device (54) is greater than the compression portion diameter (D) providing space about the Threaded Fastener (22) for allowing the Fastener axis (A) to be variously disposed rela tive to the interior space
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Easily Implantable and Stable Nail-Fastener for Skeletal Fixation and Method
Digital Commons @ Kettering University, 2012Co-Authors: Atkinson Patrick, Lecronier DavidAbstract:An intramedullary nail (20) for insertion into the medullary canal (26) in a bone (24) surrounded by the cortex (28) and defines a bore (34) extending transverse to the intramedullary nail (20). A Threaded Fastener (22) extends along a Fastener axis (A) and has a compression portion (48) having a compression portion diameter (DCP), and a Threaded portion (50) having a Threaded portion diameter (DTP) extending through a near cortex hole (40) and a far cortex hole (42), both holes (40, 42) radially overlapping the bore (34) and the Threaded portion diameter (DTP) Threadedly engaging the bore (34). A compression transmission device (54) has an exterior (56) and an interior (58) and defines an interior space for transmitting the compressional load of the Threaded Fastener (22) to the intramedullary nail (20). The Threaded Fastener (22) extends through the compression transmission device (54) and the intramedullary nail (20) and the far cortex hole (42) for Threadedly engaging the bore (34) and fixating the intramedullary nail (20) within the medullary canal (26). The interior space of the compression transmission device (54) is greater than the compression portion diameter (DCP) of the Fastener (22) for providing space at least partially about the Threaded Fastener (22) for allowing the Fastener axis (A) to be variously disposed relative to the interior space
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Compression Transmission Collar for Fastening
Digital Commons @ Kettering University, 2012Co-Authors: Lecronier David, Atkinson PatrickAbstract:A compression transmission collar apparatus for implantation into a bone with a hole having a hole wall comprising an intramedullary nail defining a bore and a Threaded Fastener and a compression transmission collar including an exterior face and a top edge and a bottom edge and a first end interstcting the top edge at an acute angle and the bottom edge at an obtuse angle and a second end intersecting the top edge at an obtuse angle and the bottom edge at an acute angle and the first end partially overlapping and opposing the second end to define a slit such that applying a compressional load to the top edge causes the first end to slide relative to and along the second end causing the compression transmission collar to compress axially and expand radially pressing the exterior face against the hole wall
Atkinson Patrick - One of the best experts on this subject based on the ideXlab platform.
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Compression Transmission Collar for Fastening
Digital Commons @ Kettering University, 2015Co-Authors: Atkinson Patrick, Lecronier DavidAbstract:A compression transmission collar apparatus (20) for implantation into a bone (22) with a hole (28) having a hole wall (32) comprising an intramedullary nail (34) defining a bore (40) and a Threaded Fastener (42) and a compression transmission collar (58) including an exterior face (64) and a top edge (60) and a bottom edge (62) and a first end (70) intersecting the top edge (60) at an acute angle and the bottom edge (62) at an obtuse angle and a second end (72) intersecting the top edge (60) at an obtuse angle and the bottom edge (62) at an acute angle and the first end (70) partially overlapping and opposing the second end (72) to define a slit (74) such that applying a compressional load to the top edge (60) causes the first end (70) to slide relative to and along the second end (72) causing the compression transmission collar (58) to compress axially and expand radially pressing the exterior face (64) against the hole wall (32)
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Easily Implantable And Stable Nail-Fastener For Skeletal Fixation And Method
Digital Commons @ Kettering University, 2013Co-Authors: Atkinson Patrick, Lecronier DavidAbstract:An intramedullary nail (20) defining a bore (34) is inserted into a medullary canal (26) of a bone (24). A Threaded Fastener (22) has a compression portion (48) presenting a compression portion diameter (D) and a Threaded portion (50) present ing a Threaded portion diameter (D). The Fastener (22) extends through a near cortex hole (40) and/or a far cortex hole (42), and the Threaded portion (22) Threadedly engages the bore (34). A compression transmission device (54) is disposed between a head (44) of the Fastener (22) and the intramedullary nail (20) for transmitting the compressional load of the Threaded Fastener (22) to the intramedullary nail (20). An interior space of the compression transmission device (54) is greater than the compression portion diameter (D) providing space about the Threaded Fastener (22) for allowing the Fastener axis (A) to be variously disposed rela tive to the interior space
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Easily Implantable and Stable Nail-Fastener for Skeletal Fixation and Method
Digital Commons @ Kettering University, 2012Co-Authors: Atkinson Patrick, Lecronier DavidAbstract:An intramedullary nail (20) for insertion into the medullary canal (26) in a bone (24) surrounded by the cortex (28) and defines a bore (34) extending transverse to the intramedullary nail (20). A Threaded Fastener (22) extends along a Fastener axis (A) and has a compression portion (48) having a compression portion diameter (DCP), and a Threaded portion (50) having a Threaded portion diameter (DTP) extending through a near cortex hole (40) and a far cortex hole (42), both holes (40, 42) radially overlapping the bore (34) and the Threaded portion diameter (DTP) Threadedly engaging the bore (34). A compression transmission device (54) has an exterior (56) and an interior (58) and defines an interior space for transmitting the compressional load of the Threaded Fastener (22) to the intramedullary nail (20). The Threaded Fastener (22) extends through the compression transmission device (54) and the intramedullary nail (20) and the far cortex hole (42) for Threadedly engaging the bore (34) and fixating the intramedullary nail (20) within the medullary canal (26). The interior space of the compression transmission device (54) is greater than the compression portion diameter (DCP) of the Fastener (22) for providing space at least partially about the Threaded Fastener (22) for allowing the Fastener axis (A) to be variously disposed relative to the interior space
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Compression Transmission Collar for Fastening
Digital Commons @ Kettering University, 2012Co-Authors: Lecronier David, Atkinson PatrickAbstract:A compression transmission collar apparatus for implantation into a bone with a hole having a hole wall comprising an intramedullary nail defining a bore and a Threaded Fastener and a compression transmission collar including an exterior face and a top edge and a bottom edge and a first end interstcting the top edge at an acute angle and the bottom edge at an obtuse angle and a second end intersecting the top edge at an obtuse angle and the bottom edge at an acute angle and the first end partially overlapping and opposing the second end to define a slit such that applying a compressional load to the top edge causes the first end to slide relative to and along the second end causing the compression transmission collar to compress axially and expand radially pressing the exterior face against the hole wall
Kazuyuki Nagata - One of the best experts on this subject based on the ideXlab platform.
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Early failure characterization of cantilever snap assemblies using the PA-RCBHT
2014 IEEE International Conference on Robotics and Automation (ICRA), 2014Co-Authors: Juan Rojas, Kensuke Harada, Hiromu Onda, Natsuki Yamanobe, Eiichi Yoshida, Kazuyuki NagataAbstract:Failure detection and correction is essential in robust systems. In robotics, failure detection has focused on traditional parts assembly, tool breakage, and Threaded Fastener assembly. However, not much work has focused on sub-mode failure classification. This is an important step in order to provide accurate failure recovery. Our work implemented a novel failure characterization scheme for cantilever snap assemblies. The approach identified exemplars that characterized salient features for specific deviations from a nominal trajectory. Then, a rule based approach with statistical measures was used to identify failure and classify failure sub-modes. Failure sub-mode classification was evaluated by using a reliability measure. Our work classified failure deviations with 88% accuracy. Varying success was experienced in correlating failure deviation modes. Cases with only 1-deviation had 86% accuracy, cases with 2-deviations had 67% accuracy, and cases with 3 deviations had 55% accuracy. Our work is an important step in failure characterization of complex geometrical parts and serves as a stepping stone to enact failure recovery.
Juan Rojas - One of the best experts on this subject based on the ideXlab platform.
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Contextualized Early Failure Characterization of Cantilever Snap Assemblies.
2016Co-Authors: Juan Rojas, Kensuke Harada, Hiromu Onda, Eiichi YoshidaAbstract:Abstract—Failure detection and correction is essential in robust systems. In robotics, failure detection has focused on traditional parts assembly, tool breakage, and Threaded Fastener assembly. However, not much work has focused on classifying failure into various sub-modes. This is an important step in order to provide accurate failure recovery. Our work implemented a contextualized failure characterization scheme for cantilever snap assemblies. A rule based approach was used through which assemblies whose trajectories deviated from the normal approach trajectory were identified in the beginning of the task. We not only identified failure but also the failure type that occurred. The method identified exemplars that characterized salient features for specific deviations from the initial approach trajectory in the assembly task. A contact-state map was generated through sampling the contact space during training. Contextualized statistical measures were used to classify trials during the testing phase. Our work classified failure deviations with 88 % accuracy. According to the statistic measures used, varying success was experienced in correlating failure deviation modes. Each case was analyzed using gaussian statistics and one and two standard deviations. Cases with trajectory deviations in one direction had {75%, 92%} accu-racy, cases with deviations in two directions had {61%, 94%} accuracy, and cases with deviations in three directions had {69%, 100%} accuracy. Our work provides further insights into the early failure characterization of complex geometrical parts which will serve to implement failure recovery techniques in the face of significant and unexpected errors. I
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Early failure characterization of cantilever snap assemblies using the PA-RCBHT
2014 IEEE International Conference on Robotics and Automation (ICRA), 2014Co-Authors: Juan Rojas, Kensuke Harada, Hiromu Onda, Natsuki Yamanobe, Eiichi Yoshida, Kazuyuki NagataAbstract:Failure detection and correction is essential in robust systems. In robotics, failure detection has focused on traditional parts assembly, tool breakage, and Threaded Fastener assembly. However, not much work has focused on sub-mode failure classification. This is an important step in order to provide accurate failure recovery. Our work implemented a novel failure characterization scheme for cantilever snap assemblies. The approach identified exemplars that characterized salient features for specific deviations from a nominal trajectory. Then, a rule based approach with statistical measures was used to identify failure and classify failure sub-modes. Failure sub-mode classification was evaluated by using a reliability measure. Our work classified failure deviations with 88% accuracy. Varying success was experienced in correlating failure deviation modes. Cases with only 1-deviation had 86% accuracy, cases with 2-deviations had 67% accuracy, and cases with 3 deviations had 55% accuracy. Our work is an important step in failure characterization of complex geometrical parts and serves as a stepping stone to enact failure recovery.
