Wyniki wyszukiwania - Biblioteka Nauki

1

The energetic and experimental based approach to description of basic material characteristics and mechanical properties of selected polymers

100%

Kurpisz D. , Obst M.

|

tom Vol. 58 nr 1

183--193

EN

The paper presents a proposal of using an experimental phenomenological approach and energy based method to the modelling of mechanical properties of nonlinear elastic mate- rials using examples of two selected polymers. On the basis of an experimental stress-strain relation, together with transversal deformation measurement and the geometrical interpre- tation of the deformation process, analytical forms of the strain energy density function and a pure volumetric part of the strain energy density function have been introduced. The volumetric part of energy has been used in the description of the material damage process interpreted as the appearance of the first plastic deformations, which is the original part of the work and continuous investigations carried out by Wegner and Kurpisz. All theoretical investigations have been illustrated using examples of PVC and PA-6.

2

Motorbike protective helmets, construction, testing and its influence on the type and severity of injuries of motorbike accident casualties: a literature review

80%

Obst M. , Rzepczyk S. , Głowiński S. , Żaba C.

|

2023

|

tom Vol. 34, nr 1

art. no. 2023118

EN

A motorcycle or moped helmet is currently mandatory, and provides basic protection to the user of a motor-powered two-wheeler against the possible consequences of a road accident. A wide market offer of various protective helmets allows one to choose from many different design solutions used by the manufacturers. The introduction of a protective motorcycle helmet is associated with the need of meeting the conditions set out in legal regulations. In recent years there have been changes in the legal provisions regarding to protective helmets and the conditions imposed on helmets are becoming more and more restrictive. There have also been changes in the conditions for conducting the helmet approval tests. Regulations valid in Europe include the Economic Commission of Europe (ECE), whereas regulations in the United States are created by the Department of Transportation (DOT). Despite the advanced construction of protective helmets, various test methods, and changes in legal regulations, the problem of the effective protection of the heads of two-wheeler users remains valid. The article presents an actual state of constructions for motorbike helmets, safety level, testing methodology and actually applicable law regulations. This analysis includes a wide medical description of motorcyclist injuries and helmet obstacle impact behaviour. Further studies are required to estimate the head and neck injuries caused by accidents involving motorcycles and other materials. Therefore, construction and testing methods should be developed accordingly. This review presents the current state of knowledge that can be used as the basis for helmet tests and medical assessments of body injuries.

3

Helmet Usage for Single-Track Vehicle Users in the Poznan Agglomeration: A Preliminary Study

80%

Obst M. , Rzepczyk S. , Karwasz A. , Głowiński S.

|

tom z. 2

51--56

EN

Accidents are inherent elements of human activity, and engineers have strived to develop safety systems to safeguard people against accidents, which are often random and unpredictable. Helmets have become the most popular means of protection over the years. They have undergone significant modifications, evolving into effective and advanced tools for head protection. Unfortunately, because helmets remain optional for bicycle users, some individuals choose to ignore safety guidelines. Methods: This research employed a survey method conducted among the residents of the Poznan agglomeration to determine the reasons behind the low adoption of helmets. A questionnaire consisting of 15 questions was distributed to 173 users of two-wheeled vehicles, including motorbikes, bicycles, mopeds, and electric scooters. Results: The findings revealed that only 41.4% of men declared using helmets, with 24.4% of women doing so. Additionally, 44.4% of the helmets in use were new, while the remaining 55.6% were purchased second-hand. Conclusion: The research indicates that individuals are more likely to wear protective helmets on older two-wheelers, and helmet usage is higher in larger cities. Therefore, it is essential to focus bicycle helmet educational campaigns on children and teenagers to improve safety awareness and encourage helmet usage.

PL

Wypadki są nieodłącznym elementem działalności człowieka, dlatego inżynierowie starają się opracować systemy bezpieczeństwa, które chronią ludzi przed wypadkami, które często są przypadkowe i nieprzewidywalne. Kaski stały się na przestrzeni lat najpopularniejszym środkiem ochrony. Przeszły istotne modyfikacje, ewoluując w skuteczne i zaawansowane narzędzia ochrony głowy. Niestety, ponieważ kaski pozostają opcjonalne dla użytkowników rowerów, niektóre osoby ignorują wytyczne dotyczące bezpieczeństwa. Metody: W badaniu wykorzystano metodę ankietową przeprowadzoną wśród mieszkańców aglomeracji poznańskiej w celu ustalenia przyczyn małej ilości noszonych kasków. Kwestionariusz składający się z 15 pytań rozesłano do 173 użytkowników pojazdów dwukołowych, w tym motocykli, rowerów, motorowerów i hulajnóg elektrycznych. Wyniki: Z przeprowadzonych badań wynika, że używanie kasków deklaruje jedynie 41,4% mężczyzn, zaś kobiet 24,4%. Dodatkowo 44,4% użytkowanych hełmów było nowych, a pozostałe 55,6% kupionych z drugiej ręki. Wnioski: Badania wskazują, że osoby częściej noszą kaski ochronne na starszych jednośladach, a ich użycie jest częstsze w większych miastach. Dlatego istotne jest skupienie kampanii edukacyjnych na temat kasków rowerowych na dzieciach i nastolatkach, aby zwiększyć świadomość bezpieczeństwa i zachęcić do używania kasków.

4

The investigations of suspension model and its experimental characteristics for the air springs of truck trailer

80%

Obst M. , Kurpisz D. , Wasilewicz P.

|

2020

|

tom Vol. 31, nr 2

art. no. 2020221

EN

Air springs applied as shock damping elements are often found in the design of variety modern truck and trailer suspensions. They can also be found as damping and stabilizing suspension elements in the passenger cars and other machines. The advantage of air springs, compared to steel coil springs or leaf springs, is a better damping quality in a wide range of frequencies. The air springs stiffness can be regulated according to the requirements and working conditions. The applied air springs also allow to stabilize the distance between the vehicle body and road level in function of loading. Some proposals of vehicle suspension models can be found in technical literature where the air spring is the main elastic subassembly. Mathematical model descriptions of the suspension with air spring for vehicles apply the thermodynamic laws and relationships between the mechanical forces of cooperating suspension elements, parts geometry (suspension arms), material stiffness (reinforced rubber) and other properties (damping). The results of own investigations on the suspension model of an air spring for cargo trailer have been taken into consideration in this paper. The presented suspension model was applied to design the frame construction of a light stanchion trailer where aerodynamic drag and construction mass were reduced. The suspension model of air springs for a trailer was applied for frame loads evaluation of the light trailer. It was also used for the strength analysis of the frame construction with the reduced mass. The estimated frame loads such as torque, normal forces and bending moments were used for strength estimation of the upgraded trailer frame.