A Study on the Improvement of the Structural Joint Stiffness for Aluminum BIW

1997 ◽  
Author(s):  
Young Woong Lee ◽  
Yong Woo Kwon ◽  
Soon Yong Kwon ◽  
Won Suk Cho
Keyword(s):  
Joint Stiffness ◽  
Structural Joint

Joint Stiffness of 3D Space Frame Thin Walled Structural Joint Considering Local Buckling Effect

2014 ◽  
Vol 660 ◽  
pp. 773-777
Author(s):  
Mohd Shukri Yob ◽  
Shuhaimi Mansor ◽  
Razali Sulaiman
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Joint Stiffness ◽  
Element Model ◽  
Joint Effect ◽  
Experimental Result ◽  
Space Frame ◽  
3D Space ◽  
Structural Joint ◽  
Thin Walled

Thin walled structure is widely used in designing light weight vehicle. For automotive industry, weight is an important characteristic to increase performance of a vehicle. Vehicle structures are built from thin walled beams by joining them using various joining methods and techniques. For a structure, its stiffness greatly depends on joint stiffness. However, stiffness of thin walled beam is difficult to predict accurately due to buckling effect. Once the beams are joined to form a structure, it will expose to joint flexibility effect. A lot of researches had been done to predict the behaviors of thin walled joint analytically and numerically. However, these methods failed to come out with satisfactory result. In this research work, finite element model for 3D space frame thin walled structural joint is developed using circular beam element by validating with experimental result. Another finite element model using rigid element is used to represent 3D space frame behavior without joint effect. The difference between these 2 models is due to joint effect. By using same modelling technique, joint stiffness for different sizes can be established. Then, the relation between joint stiffness for 3D space frame and size of beam can be obtained.

Structural Joint Stiffness of Automotive Body

1988 ◽  
Author(s):  
Toshiaki Sakurai ◽  
Yoshinobu Kamada
Keyword(s):  
Joint Stiffness ◽  
Automotive Body ◽  
Structural Joint

Controllable Compliance Joint For Human Oriented Robots

2013 ◽  
Vol 43 (1) ◽  
pp. 47-60
Author(s):  
Mihail Tsveov ◽  
Dimitar Chakarov
Keyword(s):  
Numerical Experiments ◽  
Position Control ◽  
Joint Stiffness ◽  
Joint Motion ◽  
Compliance Control ◽  
Leaf Springs ◽  
Antagonistic Actuation

Abstract In the paper, different approaches for compliance control for human oriented robots are revealed. The approaches based on the non- antagonistic and antagonistic actuation are compared. In addition, an approach is investigated in this work for the compliance and the position control in the joint by means of antagonistic actuation. It is based on the capability of the joint with torsion leaf springs to adjust its stiffness. Models of joint stiffness are presented in this paper with antagonistic and non-antagonistic influence of the spring forces on the joint motion. The stiffness and the position control possibilities are investigated and the opportunity for their decoupling as well. Some results of numerical experiments are presented in the paper too.

scholarly journals Verification of Finger Joint Stiffness Estimation Method With Soft Robotic Actuator

2020 ◽  
Vol 8 ◽  
Author(s):  
Xiang Qian Shi ◽  
Ho Lam Heung ◽  
Zhi Qiang Tang ◽  
Kai Yu Tong ◽  
Zheng Li
Keyword(s):  
Estimation Method ◽  
Joint Stiffness ◽  
Ground Truth ◽  
Clinical Score ◽  
Metacarpophalangeal Joint ◽  
Finger Joint ◽  
Joint Torque ◽  
Hand Rehabilitation ◽  
Stiffness Characteristic ◽  
Modified Ashworth Scale

Stroke has been the leading cause of disability due to the induced spasticity in the upper extremity. The constant flexion of spastic fingers following stroke has not been well described. Accurate measurements for joint stiffness help clinicians have a better access to the level of impairment after stroke. Previously, we conducted a method for quantifying the passive finger joint stiffness based on the pressure-angle relationship between the spastic fingers and the soft-elastic composite actuator (SECA). However, it lacks a ground-truth to demonstrate the compatibility between the SECA-facilitated stiffness estimation and standard joint stiffness quantification procedure. In this study, we compare the passive metacarpophalangeal (MCP) joint stiffness measured using the SECA with the results from our designed standalone mechatronics device, which measures the passive metacarpophalangeal joint torque and angle during passive finger rotation. Results obtained from the fitting model that concludes the stiffness characteristic are further compared with the results obtained from SECA-Finger model, as well as the clinical score of Modified Ashworth Scale (MAS) for grading spasticity. These findings suggest the possibility of passive MCP joint stiffness quantification using the soft robotic actuator during the performance of different tasks in hand rehabilitation.

scholarly journals Efficacy and safety of condylectomy with minimally invasive surgery in the treatment of interdigital corns of the lesser toes compared to conservative treatment

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Luis M. Marti-Martinez ◽  
Rubén Lorca-Gutierrez ◽  
Salvador Pedro Sánchez-Pérez ◽  
Jonatan Garcia-Campos ◽  
Nadia Fernández Ehrling ◽  
...  
Keyword(s):  
Minimally Invasive Surgery ◽  
Surgical Treatment ◽  
Treatment Group ◽  
Conservative Treatment ◽  
Minimally Invasive ◽  
Functional Status ◽  
Invasive Surgery ◽  
Joint Stiffness ◽  
Efficacy And Safety ◽  
Clinical And Functional Status

Abstract Background Minimally invasive surgery (MIS) procedures cause less trauma to the patient and might improve recovery. This study aimed to determine the efficacy and safety of condylectomy with MIS to treat interdigital corns of the lesser toes. Methods This prospective cohort study was conducted in seven podiatry centers. Patients with interdigital corns of the lesser toes, progressing for more than a year, with one or more recurrences in the last year following conservative treatments were eligible. The recruited patients were classified according to their treatment: conservative or surgical (condylectomy with MIS) and were compared. Patient satisfaction, pain, the clinical and functional status of the foot and the appearance of sequelae were assessed at 3 and 6 months after treatment. Results At 6 months, patients in the surgical treatment group showed no pain on pressure, which significantly differed from the conservative treatment group (p <  0.001). They also improved clinical and functional status of the foot, reaching values comparable to those of the standard population. No paresthesia, joint stiffness or instability, toe malalignment, or corn transfer to a contiguous site resulted from the surgical treatment. Conclusions Condylectomy with MIS is effective and safe to treat interdigital corns of the lesser toes.

scholarly journals Which patient-reported outcomes do rheumatology patients find important to track digitally? A real-world longitudinal study in ArthritisPower

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
W. Benjamin Nowell ◽  
Kelly Gavigan ◽  
Carol L. Kannowski ◽  
Zhihong Cai ◽  
Theresa Hunter ◽  
...  
Keyword(s):  
Physical Function ◽  
Lupus Erythematosus ◽  
Patient Reported Outcomes ◽  
Treatment Effectiveness ◽  
Time Window ◽  
Joint Stiffness ◽  
Summary Score ◽  
Longitudinal Tracking ◽  
Patient Reported

Abstract Background Patient-reported outcomes (PROs) are increasingly used to track symptoms and to assess disease activity, quality of life, and treatment effectiveness. It is therefore important to understand which PROs patients with rheumatic and musculoskeletal disease consider most important to track for disease management. Methods Adult US patients within the ArthritisPower registry with ankylosing spondylitis, fibromyalgia syndrome, osteoarthritis, osteoporosis, psoriatic arthritis, rheumatoid arthritis, and systemic lupus erythematosus were invited to select between 3 and 10 PRO symptom measures they felt were important to digitally track for their condition via the ArthritisPower app. Over the next 3 months, participants (pts) were given the option to continue tracking their previously selected measures or to remove/add measures at 3 subsequent monthly time points (month [m] 1, m2, m3). At m3, pts prioritized up to 5 measures. Measures were rank-ordered, summed, and weighted based on pts rating to produce a summary score for each PRO measure. Results Among pts who completed initial selection of PRO assessments at baseline (N = 253), 140 pts confirmed or changed PRO selections across m1–3 within the specified monthly time window (28 days ± 7). PROs ranked as most important for tracking were PROMIS Fatigue, Physical Function, Pain Intensity, Pain Interference, Duration of Morning Joint Stiffness, and Sleep Disturbance. Patient’s preferences regarding the importance of these PROs were stable over time. Conclusion The symptoms that rheumatology patients prioritized for longitudinal tracking using a smartphone app were fatigue, physical function, pain, and morning joint stiffness.

scholarly journals Development of an Exoskeleton-Type Assist Suit Utilizing Variable Stiffness Control Devices Based on Human Joint Characteristics

Actuators ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 17
Author(s):  
Seigo Kimura ◽  
Ryuji Suzuki ◽  
Katsuki Machida ◽  
Masashi Kashima ◽  
Manabu Okui ◽  
...  
Keyword(s):  
Joint Stiffness ◽  
Knee Extensor ◽  
Artificial Muscle ◽  
Variable Stiffness ◽  
Lower Limbs ◽  
Joint Characteristics ◽  
Standing Up ◽  
Maximum Decrease ◽  
Control Devices ◽  
The Relationship

In this paper, the prototype of the assistive suit for lower limbs was developed. The prototype was based on an assist method with joint stiffness and antagonized angle control. The assist method comprises a system consisting of a pneumatic artificial muscle and a pull spring, which changes the joint stiffness and the antagonized angle to correspond to the movement phase and aims at coordinated motion assistance with the wearer. First, the characteristics of the developed prototype were tested. It was confirmed that the measured value of the prototype followed the target value in the relationship between torque and angle. In addition, there was hysteresis in the measured value, but it did not affect the assist. Next, the evaluation of standing-up and gait assist by measuring electromyography (EMG) of the knee extensor muscle was conducted using the prototype. In all subjects, a decrease in EMG due to the assist was confirmed. In one subject, the maximum decrease rate at the peak of the EMG was about 50% for standing-up motion and about 75% for gait motion. From the results of these assist evaluations, the effectiveness of the assist method based on the joint stiffness and antagonistic angle control using the prototype was confirmed.

Similarities in joint stiffness across footwear conditions in younger and masters-aged runners

2021 ◽  
pp. 1-11
Author(s):  
Brianne Borgia ◽  
Kara N. Radzak ◽  
Julia Freedman Silvernail
Keyword(s):  
Joint Stiffness
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